chemistry exam 2 – Flashcards

Which of the following elements has six valence electrons?
Be
B
C
Correct!
O

Which molecule is most polar?
S=C=S
O=C=O
Correct!
O=C=S
These all have the same polarity.

Take enough money away from your bank account and the bank will show a negative credit. Take an electron away from an atom, however, and the atom shows up positive. Explain.
Electrons are already negative. Therefore, we know from basic math that subtracting a negative (number) from a neutral (atom), will make the result positive.
Correct!
Neutral atoms contain identically charged but oppositely signed protons and electrons. Removing one of the negative electrons results in an excess of positively charged protons.
Removing an electron from an atom does not have the atom show up positive. It simply leaves the atom short one electron.
Atoms are constantly exchanging electrons. Having an atom “show up positive” is only an expression indicating that it has taken its turn in the game of electron exchange.

Given that the total number of atoms on our planet remains fairly constant, how is it ever possible to deplete a natural resource such as a metal?
The problem remains that not everyone recycles as they should.
Recycling only forestalls the inevitable depletion of metal resources.
You Answered
The atoms don’t leave our planet, which is why naturally occurring materials never really reach the point of depletion.
Correct Answer
The problem is with the expense of collecting metal atoms that are uniformly dispersed.

What is the molecular shape of the SF_2
S
F
2
molecule?

linear
Correct Answer
bent
You Answered
tetrahedral
octahedral

Which of the following has the greatest number of nonbonding pairs of electrons?
C
H
He
Correct!
F

How many covalent bonds would the O atom usually form?

1
Correct!
2
4
6

Distinguish between a metal and a metal-containing compound.
There is no distinction between the two.
Correct!
Only one of these contains ionic bonds.
Only one of these contains covalent bonds.
Only one of these occurs naturally.

Which of the following molecules would contain a dipole?
Correct Answer
H-F
You Answered
Cl-Cl
H-H
F-F

Two liquids, A and B, have very different physical properties. A and B do not mix. A boils at 80°C and freezes at -30°C. B boils at 35°C and freezes at -100°C. Molecules of which are likely to have the largest dipole?
Correct Answer
molecule A
molecule B
Not enough information was given.
You Answered
Both have similar dipoles.

An individual carbon-oxygen bond is polar. Yet carbon dioxide is nonpolar because ________.
(A) the molecule has an even number of electrons
(B) it’s symmetry
You Answered
(C) the electron-pulls of the two oxygen atoms are equal and opposite
Correct Answer
B and C

The principal source of an atom’s electronegativity is the ________.
repulsive force occurring among electrons within the same shell
repulsive force occurring between electrons within neighboring shells
Correct!
effective nuclear charge
the kinetic energy electrons have orbiting the nucleus

Electron dot structures are not so important for understanding ________.
ionic bonds
Correct!
metallic bonds
covalent bonds
polar covalent bonds

Which would you expect to have a higher melting point: sodium chloride, NaCl, or cesium chloride, CsCl? Why?
The cesium chloride has a higher melting point because larger ions of the same charge are able to attract more ions of the opposite charge.
The cesium chloride has a higher melting point because its ions are smaller, which makes the charges more dense.
The sodium chloride has a higher melting point because of the greater charges of the ions, and hence the greater force of attractions between them.
Correct!
The sodium chloride has a higher melting point because its ions are smaller, which allows oppositely charged ions to get closer.

How do the electron-dot structures of elements in the same group in the periodic table compare with one another?
The structures differ by exactly two electrons between vertically consecutive elements.
The number of valence shell electrons increases by one for each element from the top to the bottom of the group.
Correct!
Elements of the same group have the same number of valence electrons.
The number of electrons in the electron-dot-structure will equal the group number for each element of the group.

How many chloride ions (Cl1-) are needed to balance the positive charge of a barium ion (Ba2+)?
Correct!
2
1
3
0

Which of the following molecules contains an ionic bond?
Correct!
MgCl2
Cl2
SF3
Cl2O7

Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
These atoms are too large to be able to come in close contact with other atoms.
Correct!
They have a great tendency to lose electrons.
Their valence shells are already filled with electrons.
They are on the wrong side of the periodic table.

Ammonia is more polar than is borane because it ________.
has a lone pair of electrons
is less symmetrical than borane
its hydrogens are not exactly opposite one another
Correct!
all of the above

When is the electronic geometry of a molecule not the same as its molecular shape?
Correct!
when one or more of the substituents is a lone pair of electrons
when there are an odd number of electron pairs as substituents
when there are an odd number of electrons surrounding the central atom
The geometry of a molecule is always the same as its shape

How many substituents are on the nitrogen atom in NH4+?

1
3
You Answered
5
Correct Answer
4

What surrounds the sulfur atom in SF4?
four substituent fluorine atoms
Correct!
four substituent fluorine atoms plus one lone pair of electrons
four substituent fluorine atoms plus two lone pairs of electrons
four substituent fluorine atoms plus three lone pairs of electrons

What is the name for the following polyatomic ion?

CH3CO2-

triacetate
monocarboxylate
Correct!
acetate
acidic

If a neutral atom loses one electron, what is the electrical charge of the atom?
-1
Correct!
+1
-2
+2

What is the molecular shape of the ammonia molecule?

Correct!
pyramidal
bent
tetrahedral
T-shaped

The neon atom tends NOT to gain any additional electrons because ________.
its nuclear charge is not great enough
that would result in a positive ion
of the repulsions they would experience with electrons in the same shell
Correct!
there is no more room available in its outermost occupied shell

How is it possible for a neutral molecule, such as water, to form an ion?
Correct!
It can combine with a hydrogen ion to form a positively charged species.
It can combine with a chloride ion to form a negatively charged species.
It can fragment into protons and electrons.

How many electrons are used to draw the electron-dot structure for hydrogen peroxide?
4
7
8
Correct!
14

Which of the following molecules is most likely to show a hydrogen bonding interaction?
Correct!
(A) CH3OH
(B) CH3SH
(C) CH4
(D) H-C-C-H
(E) A, B and C

Fluorine is a relatively ________.
large atom
soft atom
Correct!
small atom
greenish atom

Fish don’t live very long in water that has just been boiled and brought back to room temperature. Suggest why.
There is now a higher concentration of dissolved CO2 in the water.
The nutrients in the water have been destroyed.
Since some of the water was evaporated while boiling, the salts in the water are now more concentrated. This has a negative effect on the fish.
Correct!
The boiling process removes most of the air that was dissolved in the water. Upon cooling the water is void of its usual air content, hence, the fish drown.

If you need 3.01 × 1023 molecules of sucrose, how many liters of a 4.00 molar solution would you need?
Correct!
0.125 L
0.250 L
4.00 L
1.00 L

Which of the following is most likely to have the weakest induced dipole-induced dipole interaction?
Cl2
Br2
Correct!
F2
I2
All of the above have the same interactions.

Describe what usually happens to a hot solution that is saturated with a solid as it cools.
The solid that is dissolved comes out of the solution completely.
The solid stays in the solution.
Correct!
Some of the solid comes out of the solution.
The solution freezes.

Which of the following would have the weakest induced dipole-induced dipole interactions?
Correct!
C6H14
C8H18
C10H22
C12H26
not enough information given

Red blood cells have a high concentration of dissolved ions. When placed into pure water they rupture. Why?
Correct!
Osmosis draws water into the cell until it pops.
Water dissolves the cell membrane.
Osmosis draws water out of the cell until it tears.
The cells are not stable outside of a biological host.

Cells at the top of a tree have a higher concentration of sugars than cells at the bottom. How might this fact assist a tree in moving water upward from its roots?
Cells with high concentrations of sugar are more dense. As these cells migrate downwards, cells containing fresh water are able to migrate upwards.
Correct!
Water is pushed upwards by osmostic pressure.
It doesn’t. In fact, water makes it to the top of a tree because that is where the water molecules are being evaporated.
Fresh water is drawn upwards to the sugar containing cells by way of dipole-dipole molecular interactions.

Which of the following is the strongest form of intermolecular attraction?
a chemical bond
Correct!
an ion-dipole interaction
a dipole-dipole interaction
a dipole-induced dipole interaction
an induced dipole-induced dipole interaction

How many molecules of sucrose are in 0.5 00L of a 2.00 molar solution of sucrose?
3.01 × 1023 molecules of sucrose
Correct!
6.02 × 1023 molecules of sucrose
12.04 × 1023 molecules of sucrose
1 gram

What happens if you were to place a concentrated solution into a bag made of a semipermeable membrane and were to then suspend it in a very dilute solution?
The size of the suspended bag would decrease.
Correct!
The size of the suspended bag would increase.
The size of the bag would not change.
The solutions would eventually reach the same concentration.

Which of the following would have the highest boiling point?
Cl2
Br2
F2
Correct!
I2
not enough information given

What is the main difference between a dipole-dipole interaction and a dipole-induced dipole interaction?
Correct!
Both are similar, but one involves a temporary dipole created by a permanent dipole.
Dipole-dipole interactions are weaker because the dipoles are permanent.
Dipole-induced dipole interactions are stronger because the induced dipoles can be formed at any time.
Both are identical.

If an ionic bond is stronger than a dipole-dipole interaction, how can water dissolve an ionic compound?
Correct!
The ion-dipole interactions of a bunch of water molecules gang up on the strong ionic bond and pull it into the solution.
The ionic bond is weakened by the ion-dipole interactions and ionic repulsion ejects the ions from the crystal.
The ion-dipole interaction causes the ions to heat up and vibrate free of the crystal.
The ions never overcome their interatomic attraction and therefore are not soluble.

Why are the melting temperatures of most ionic compounds far greater than the melting temperatures of most covalent compounds?
Correct!
Ionic bonds are so much stronger than the intermolecular attractions between covalently bonded compounds.
Covalent bonds are not as strong as ionic bonds.
As a solid, salts have a very organized crystalline structure which takes a lot of energy to break apart.
Most covalent compounds have at least one weak bond in their structure that is easily broken when heat is added.

How can you tell whether a sugar solution is saturated or not?
Add more sugar, if it dissolves, it is saturated.
There will be a precipitate if the water is heated.
As long as there are more water molecules than sugar molecules, there is a saturated solution.
Correct!
Add more sugar. If it does not dissolve after mixing, the solution is saturated.

What is a hydrogen bond?
Correct!
a special type of dipole-dipole attraction involving hydrogen bound to a highly electronegative atom
a special type of dipole-dipole attraction involving hydrogen bound to any other atom
a special type of dipole-dipole attraction involving hydrogen bound to another hydrogen atom
a special type of attraction involving any molecules that contain hydrogens

Why do red blood cells, which contain an aqueous solution of dissolved ions and minerals, burst when placed in fresh water?
The dissolved ions provide a pressure that eventually bursts open the cell.
Correct Answer
More water molecules enter the cell than leave the cell.
You Answered
The fresh water acts to dissolve the blood cell wall.
all are correct

Hard water contains excessive amounts of ________.
chlorine ions
Correct!
calcium ions
hydrogen ions
hydroxide ions

How is the solubility of a solid affected by temperature?
As temperature goes up, the solubility goes up.
As temperature goes down, the solubility goes down.
As temperature goes up, the solubility goes down.
As temperature goes down, the solubility goes up.
Correct!
It depends on the solid

Which of the following accurately describes osmosis?
Correct!
The more concentrated solution absorbs water from the less concentrated solution.
The less concentrated solution absorbs water from the more concentrated solution.
The less concentrated solution gets more dilute.
The ions migrate from the more concentrated solution to the less concentrated.

Would you expect to find more dissolved oxygen in polar or tropical ocean waters? Why?

There would be more dissolved oxygen in the tropical oceans because intense tropical storms mix up the atmospheric oxygen into the ocean water.
There would be more dissolved oxygen in the polar oceans because the colder oxygen would “sink” and dissolve into the water.
There would be more dissolved oxygen in the tropical oceans because the heated oxygen molecules in the air would collide with and mix into the water.

Correct!
There would be more dissolved oxygen in the polar oceans because the solubility of oxygen in water decreases with increasing temperature.

What is the difference between a dipole-dipole interaction and an ion-dipole interaction?
one involves hydrogen bonding while the other does not
one involves salts and water while the other doesn’t involve water
one involves ionic molecules interacting with other ionic molecules while the other deals with polar molecules

Correct!
one involves dipole attraction between molecules while the other involves dipole interactions between molecules and ions

A dipole is a ________.

Correct!
separation of charges
molecule with parallel bonds
nonpolar entity
form of electronegativity

Hydrogen chloride, HCl, is a gas at room temperature. Would you expect this material to be very soluble or not very soluble in water?

Correct!
HCl is very soluble in water by virtue of the dipole/dipole attractions occurring between the HCl and H2O molecules.

It is not very soluble because it is a gas, and all gases have very low solubility in water at room temperature.
HCl is very soluble in water because it is such a small molecule, there is little electrical attraction to other HCl molecules.
It is not very soluble because as a gas with low density, it floats to the surface of the water and then into the surrounding atmosphere.

An inventor claims to have developed a new perfume that lasts a long time because it doesn’t evaporate. Comment on this claim.

A perfume that does not evaporate could be toxic since the molecules never leave the skin.

Correct!
In order to smell something, the molecules must evaporate and reach your nose. If the new perfume doesn’t evaporate, it will not have an odor.
This would be impossible to make because the perfume would have to be pressurized in order to not evaporate.
This product is sure to sweep the market making many happy customers.

How many grams of sugar (sucrose) are there in 5.0 liters of sugar water that has a concentration of 0.50 grams per liter of solution?
50 g
25 g
Correct!
2.5 g
1.5 g

How are intermolecular forces and solubility related?
Correct!
Solubility depends on the solvent’s ability to overcome the intermolecular forces in a solid.
Solubility depends on the solute’s ability to overcome the intermolecular forces in the solvent.
Solubility is a measure of how strong a solvent’s intermolecular forces are.
Solubility is a measure of how weak the intermolecular forces in the solute are.

Under which of the following conditions would you expect the highest solubility of oxygen gas in water?
high temperature and low pressure above the solution
Correct!
low temperature and high pressure above the solution
low temperature and low pressure above the solution
high temperature and high pressure above the solution

Which of the following molecules is most likely to show a dipole-dipole interaction?
Correct!
CH3OH
CH3SH
CH4
H-C-C-H
A and B

A soap molecule is ________.
primarily polar
primarily nonpolar
Correct!
a molecular with both a polar and nonpolar part
a neutral compound

A sample of steel is composed of 5 percent carbon and 95 percent iron. Which is the solvent?
Correct!
iron
carbon
steel
Steel is not a solution, it is a mixture.
A solid cannot be a solvent.

Which of the following molecules is most likely to show a dipole-dipole interaction?
Correct!
SO2
CO2
CH4
H-C-C-H

Which of the following would have the highest boiling point?
C6H14
C8H18
C10H22
Correct!
C12H26

Why are ion-dipole attractions stronger than dipole-dipole attractions?
The chemical bond in an ion-dipole molecule is similar also a covalent bond.
Correct!
The magnitude of the electric charge associated with an ion is much greater.
Dipole areas are subject to changing from positive to negative regions on the molecule.
Like charge (dipole) does not attract like charge (another dipole.)

How many grams of sodium chloride are needed to make 15 L of a solution that has a concentration of 3.0 g per liter of solution?
30. g
141 g
5.0 g
Correct!
45 g

What is molarity?
the number of grams of solute per liter of solution
You Answered
the number of moles of solute per liter of solvent
the number of liters of solute per mole of solution
Correct Answer
the number of moles of solute per liter of solution

When you set a pot of tap water on the stove to boil, you’ll often see bubbles start to form well before boiling temperature is ever reached. Explain this observation.
These are dissolved salts heating up and escaping from the water.
These bubbles are formed as the surrounding gases from the air dissolve into the water as it is heated.
They are very minute pockets of water in the gaseous phase. When they get large enough, the water will boil as this gas escapes.
Correct!
These initial bubbles are the gases that were dissolved in the water coming out of solution. The solubility of gases in water decreases with increasing temperature.

Treating water with chlorine or ozone during water purification is an example of ________.
a physical change
Correct!
a chemical reaction
ion exchange
a solid dissolving in a liquid

Which of the following molecules would you expect to be the most strongly attracted to a Cl- ion?
Correct!
H-F
H3C-CH3
Cl-Cl
F-F
CCl4

Which of the following solutions is the most concentrated?
one liter of water with 1 gram of sugar
one liter of water with 2 grams of sugar
one liter of water with 5 grams of sugar
Correct!
one liter of water with 10 grams of sugar

If the solubility of a compound is 72 grams per liter at a given temperature, how many grams of the compound will dissolve in 0.50 liters at the same temperature?
Correct!
36 g
72 g
144 g
30 g

Why might a solvent like turpentine be better for removing grease and grime than water?
Like dissolves like.
Oil and grease have similar interatomic forces as the turpentine and so are more soluble.
Water is too polar and doesn’t interact well with the nonpolar oils.
Oil and grease have very limited solubility in the water.
Correct!
all of the above

How many molecules of sucrose are in 0.500 L of a 1.00 molar solution of sucrose?
Correct!
3.01 × 1023 molecules of sucrose
6.02 × 1023 molecules of sucrose
12.04 × 1023 molecules of sucrose
0.5

In which of the following molecules will water induce a temporary dipole?
CO2
O2
N2
Correct!
all of them
none of them

A 1 molar solution of sucrose (Formula Weight 342.6 g/mol) solution contains ________.
1 mole of sucrose
342.6 g of sucrose
6.02:times10^{23} molecules of sucrose
Correct!
all are correct

Does a plastic bottle of fresh water sink or float in the ocean? Why?
Sinks; The combined density of the plastic bottle plus the fresh water inside is greater than the density of the ocean water.
Correct!
Floats; The bottle filled with fresh water floats in ocean water because it is less dense than the ocean water.
Floats then sinks; The bottle filled with fresh water floats in ocean water until the fresh water reaches the same temperature as the ocean water, at which point it sinks.
Sinks slightly; The added density of the plastic bottle will cause the bottle to sink slightly. It would most likely sink less than a foot where the density of the ocean water would be equal to or greater than the bottle of fresh water.

A solid has a solubility at room temperature of 78 grams per liter. If 1.0 L of a heated solution containing 100. g of solute is cooled to room temperature, how much solid is formed?
100 g
Correct!
22 g
78 g
1 L

In a solution made from one teaspoon of sugar and one liter of water, which is the solute?
water
Correct!
sugar
both sugar and water
none of the above

Which of these statements about boiling point is incorrect?

I. Boiling occurs when sufficient molecular energy to convert a liquid to a gas.
II. The stronger the cohesive forces the higher the boiling point.
III. Boiling results in the cleavage of chemical bonds.
I only
II only
Correct!
III only
I and III
II and III

The stronger the cohesive forces in a substance
Correct!
the higher the boiling point and the melting point.
the lower the boiling point and higher the melting point.
the lower the boiling point and the melting point.
the higher the boiling point the lower the melting point.
Boiling and melting point are independent of forces.

Which of these is not a unique property of water?

I. expands when it freezes
II. nonpolar molecules
III. a good solvent
I only
I and III
Correct!
II only
II and III
III only

The rise of a liquid up a narrow test tube is due to
Correct!
capillary action: an interplay of both cohesive and adhesive forces
cohesive forces only
adhesive forces only
ionic forces

The amount of heat energy required to change a solid to a liquid is known as:
heat of change
heat of vaporization
Correct!
heat of melting
heat of sublimation

Which of the following statements are true concerning water:

(i) ice is less dense than liquid water

(ii) adhesive forces are responsible for attraction between water molecules and different substances

(iii)water beads form due to surface tension

(iv) condensation is a warming process while evaporation is a cooling process

Correct!
(A) i, ii, iii and iv
(B) ONLY ii and iii
(C) ONLY i
(D) None of the statements are true

Which of these substances would have the weakest cohesive forces in combination with extremely high molecular mobility?
H2O(l)
Correct!
CH4(g)
KCl(s)
N2(l)
Au(s)

Which of these substances would have the strongest cohesive forces in combination with the greatest molecular mobility?
Correct!
H2O(l)
CH4(g)
KCl(s)
O2(g)
Au(s)

Which of these substances would you expect to have the lowest boiling point?
diamond
graphite(pencil lead)
water
Correct!
pentane
lead

Surface tension in water is a result of:
Correct!
hydrogen bonds
ionic bonds
London dispersion forces
none of the above

Which of these substances, existing as a liquid, contains hydrogen bonds?

I. NH3
II. H2O
III. C2H5OH
IV. CH 3CH3
I only
II, III and IV
I and II
II and III
Correct!
I, II and III

Which of these describes the process by which a liquid molecule at the surface of a liquid escapes to the gas phase?
melting
sublimation
Correct!
evaporation
deposition
condensation

Which of these statements about liquids is correct?

I. Increased molecular motion will result increased rate of evaporation.
II. Liquids will take the shape of their container.
III. Liquids have relatively low compressibility.
I only
II only
I and II
II and III
Correct!
I, II and III

Which of these correctly describes solids with a well-ordered structure?
cohesive
Correct!
crystalline
amorphous
neat
compressed

Why do ponds not freeze from the bottom up, i.e, fish and other living organisms survive winter by living beneath the frozen crust of a lake:
water does freeze from the top up; all fish must migrate to warmer waters during winter
the kinetic energy of water is high enough to keep it from completely freezing
the body heat from the fish keep the water from freezing
Correct!
below 4C, the surface water cools to below 4C, becomes less dense than the water below it and therefore doesn’t sink

Which of the following statements is not true as regards the specific heat of water:

(i) water has a higher specific heat than iron

(ii) water has a high specific heat because much of the heat added to water is consumed in breaking hydrogen bonds

(iii) water has a high specific heat because much of the heat applied to water is converted to kinetic energy

(iv) water has a high specific heat because much of the heat applied to water is converted to potential energy

(A) i
(B) ii
Correct!
(C) iii
(D) i and iv

Which of these factors will not affect the melting point of a substance?
cohesive forces
temperature
molecular motion
molecular structure
Correct!
All of these will affect the melting point.

Which of these is a benefit of waters unique freezing properties?
Correct!
Water insulates lakes which freeze on the surface in the winter.
Icebergs sink to the bottom of the ocean cooling volcanic eruptions.
Water is so small that it contributes little to erosion.
Freezing of cells allows for extended preservation of the cells.
Flash freezing results in the destruction of a food sample.

Which of these statements about water is incorrect?
Water has a high boiling point.
Water expands when it freezes.
Water is the most abundant liquid on the planet.
Water molecules hydrogen bond with other water molecules.
Correct!
All of these are correct statements.

Which of these statements about cohesive forces are correct?

I. In the absence of cohesive forces, most substances would be solids.
II. Cohesive forces result in the formation of liquid droplets or spheres.
III. A spherical shape minimizes surface-area to volume ratio.
I only
II only
I and III
Correct!
II and III
I and II

Which of the statements about solids are correct?

I. Solids have lower kinetic energy than liquids.
II. Molecules within solids are completely motionless.
III. The shape of a solid is independent of the container which holds it.
I only
II only
I and II
II and III
Correct!
I and III

Which of the statements about liquids is incorrect?
Liquids are highly disordered when compared with solids.
Liquids have high molecular motion when compared with solids.
Correct!
Liquids have a relatively fixed shape when compared with solids.
Liquids have strong molecular attractions when compared with gases.
Liquids have a relatively low compressibility when compared with gases.

The point at which a liquid is converted to a gas is known as the ____.
Correct!
boiling point
melting point
sublimation point
deposition point
freezing point

Ice floats in water because
Correct!
hydrogen bonds hold the water molecules in the ice in an open crystalline structure that makes it less dense than water
as more ice forms, its weight increases the density of the water
kinetic energy of the ice is greater than that of water
none of the above

Substance A contains stronger cohesive forces than substance B. Which is true?
Substance A will have a higher boiling point and higher vapor pressure than substance B.
Substance A will have a lower boiling point and lower vapor pressure than substance B.
Substance A will have a lower boiling point and higher vapor pressure than substance B.
Correct!
Substance A will have a higher boiling point and lower vapor pressure than substance B.
Can’t tell from the given information.

How many moles of oxygen gas are needed to react with 9 moles of acetylene,C2H2?

2C2H2 + 5O2(g) ? 4CO2 + 2H2O

You Answered
0.4 moles
4.5 moles
9 moles
18 moles
Correct Answer
22.5 moles

Metals tend to ____ electrons and form ions with a ____ charge?
Correct!
lose, positive
lose, negative
gain, positive
gain, negative
lose , zero

For an ionic compound, X2Y5, if the charge on each Y ion is ?2, the charge on each X ion is:
?2
?5
?10
+10
Correct!
+5

How many moles of calcium atoms are 2.5 moles of calcium carbonate, CaCO3?
1 mole
1.25 moles
Correct Answer
2.5 moles
You Answered
5.0 moles
100 moles

How many grams of carbon dioxide are produced when 18.5 moles of oxygen react with acetylene,

2C2H2 + 5O2(g) ? 4CO2 + 2H2O
You Answered
2,035 grams
814 grams
Correct Answer
651 grams
88 grams
37 grams

Which of these substances is a compound?
air
salt water
gasoline
Correct!
salt
lemonade

Nicotine has the chemical formula C10H14N2. What is the molecular weight of nicotine?
26 amu
81 amu
138 amu
Correct!
162 amu
366 amu

How many grams of methanol (CH3OH) are produced when 5.00 kg of H2 reacts with excess carbon monoxide?

CO + 2H2 ? CH3OH
40 g
You Answered
80 g
320 g
640 g
Correct Answer
40,000 g

Which of these is an ionic compound?
NCl3
Correct!
Li2O
PF5
CH4
I2

How many moles of carbon are atoms are in 1.574 g of novocain, C13H21N2O2Cl?
0.01008 moles
0.005776 moles
Correct!
0.07510 moles
0.12096 moles
0.006148 moles

Which statement about ionic compounds is incorrect?
Ionic compounds contain nondirectional bonds.
Ionic solids dissolved in water will conduct electricity.
Ionic bonds are formed between metals and nonmetals.
Correct!
Ionic bonds involve the sharing of electrons by metals and nonmetals.
Ionic compounds are held together by attraction between positive and negative ions.

How many grams of nitrogen dioxide are required to produce 260 grams of nitrogenmonoxide?

3NO2 + H2O ? 2HNO3 + NO
8.67 grams
You Answered
56.52 grams
132 grams
399 grams
Correct Answer
1196 grams

Which of these is the correct formula for aluminum oxide?
Al2O2
Correct!
Al2O3
AlO
Al3O2
AlO2

Which is of these is the correct chemical formula for carbon tetrachloride?
CCl3
Correct!
CCl4
CCl5
C4Cl
None of the above

Which of the following does not contain the same number of chlorine atoms as 60 CCl4 molecules?
240 HCl molecules
120 chlorine molecules
You Answered
40 SCl6 molecules
80 CFCl3 molecules
Correct Answer
60 CHCl3 molecules

Using the old English measurements of volume listed, determine the number of gallons in two gills.

1 gill = 1 noggin 1 butt = 2 hogsheads
1 kilderkin = 2 firkins 1 firkin = 9 gallons
1 hogshead = 52.458 gallons 1 peck = 64 noggins
1 peck = 2 gallons

0.0039 gallons
64 gallons
Correct!
0.0625 gallons
512 gallons
2304 gallons

How many grams of water are produced when 10.0 grams of O2 react with excess H2?

2H2 + O2(g) ? 2H2O
Correct!
11.25 grams
20 grams
46 grams
180 grams
360 grams

Which of these is the correct formula for potassium phosphate?
KPO4
Correct!
K3PO4
K(PO4)3
K2(PO4)3
K3P

Using the old English measurements of volume listed, determine the number of hogsheads in five kilderkins.

1 gill = 1 noggin 1 butt = 2 hogsheads
1 kilderkin = 2 firkins 1 firkin = 9 gallons
1 hogshead = 52.458 gallons 1 peck = 64 noggins
1 peck = 2 gallons
Correct Answer
1.72 hogsheads
2.91 hogsheads
You Answered
90 hogsheads
4,721 hogsheads
42,489 hogsheads

Which of these is the correct name for NaHCO3?
sodium carbonate
sodium trioxide
sodium monocarbide
Correct!
sodium bicarbonate
sodium carbide oxide

Which of these statements about covalent compounds is incorrect?
You Answered
Covalent bonds involve the combination of two nonmetals.
Correct Answer
Covalent compounds dissolve in water to form electrolyte solutions.
Covalent compounds contain atoms which share electrons to gain stability.
The bonds in covalent compound are often oriented in a particular direction.
Electrons in covalent compounds are not always equally shared between atoms.

What is the molecular weight of PCl3?
66.5 amu
106.5 amu
Correct Answer
137.5 amu
You Answered
180 amu
360 amu

Which of these will not form a positive ion in an ionic compound?
You Answered
Ba
Rb
Correct Answer
P
Sn
Mg

Determine the number of moles in a 1.95 × 10?2 gram sample of the amino acid glycine, CH2(NH2)CO2H.
Correct Answer
2.6 × 10?4 moles
2.6 × 10?2 moles
1.46 moles
You Answered
2.0 × 10?2 moles
3.85 × 10?1 moles

Which of these is the correct SUM of the coefficients when the equation is balanced?

__ CaCl2(aq) + __ K2CO3(aq) ? __ KCl(aq) + __ CaCO3(s)
2
4
Correct!
5
8
10

How many grams of gallium are there in a 145 gram sample of gallium arenside, GaAs?
74.9 g
Correct!
69.7 g
145 g
6.02 × 1023 g

Why is it important for a chemist to know the relative masses of atoms?
You Answered
There are not that many different kinds of atoms and so it’s important to know how they relate to one another.
Correct Answer
It provides information about how many atoms two samples have relative to each other
It provides an indication of how the different atoms will interact
Because the mass of an atom is directly related to its chemical properties.

Which of the following has the greatest mass?
Correct Answer
1 mole of Pb
1 mole of H2
You Answered
1 mole of Be
1 mole of Na
All have the same mass.

How many grams of water can be formed from the reaction between 10 grams of oxygen and 1 gram of hydrogen?
You Answered
11 grams of water are formed since mass must be conserved.
10 grams of water are formed since you can’t get a greater mass of water produced than oxygen reacting.
Correct Answer
9 grams of water are formed because oxygen and hydrogen react in an 8:1 ratio.
No water is formed because there is insufficient hydrogen to react with the oxygen.

The ________ is what needs to be overcome in a reaction so that it can proceed to the products.
bond energy
catalyst
entropy
thermodynamics
Correct!
activation energy

Assume air has an average molar mass of 28 grams/mole, and determine how many moles of air molecules there are 1.0 liters of air, which contains 1.26 grams of air molecules.
28 moles
0.45 mole
Correct!
0.045 mole
22.4 moles

According to the following balanced chemical equation, if you want to generate two moles of H2O how many grams of O2 do you need?

2 H2 + O2 ? 2 H2O
Correct!
32
16
8
4
6.022 × 1023

If it takes 20 beryllium atoms to equal the mass of two krypton atoms, what is the relative mass of beryllium compared to krypton?
Correct!
1/10
1/20
40 times
100 times
10 times

Entropy is a measure of ________.
disorder
Correct Answer
the spreading of energy
solar energy
You Answered
thermodynamics

Given the following generic chemical reaction, which is correct

X ? Y
X is the product.
Correct!
Y is the product.
? is the product.
Both X and Y are the products.
Both X and Y are the reactants.

Given that the bond energy of N2 is 946 kJ/mole, the bond energy of O2 is 498 kJ/mole and the NO bond energy is 631 kJ/mole, how much energy is required to react 1 mole of nitrogen molecules according to the following reaction?

N2 + O2 ? 2 NO
Correct!
182 kJ
-182 kJ
813 kJ
-813 kJ

How many moles of water, H2O, are produced from the reaction of 16 grams methane, CH4, with an unlimited supply of oxygen, O2. How many grams of water is this?

CH4 + 2H 2 O? CO2 + 2 H2O
0.889 mole, which is 16 grams
2.0 moles of water, which is 32 grams
Correct!
2.0 moles of water, which is 36 grams
1.0 mole of water, which is 18 grams

Balance the following equation.

____ NO ? ____ N2O + ____ NO2
Correct!
3, 1, 1
3, 0, 0
4, 4, 8
1, 2, 4
6, 2, 1

Ozone, O3, is ________.
a pollutant
a naturally occurring compound
an elemental material
Correct!
all of the above

Why might increasing the concentration of a set of reactants increase the rate of reaction?
Correct Answer
You have increased the chances that any two reactant molecules will collide and react.
You have increased the ratio of reactants to products.
You Answered
The concentration of reactants is unrelated to the rate of reaction.
The rate of reaction depends only on the mass of the atoms and therefore increases as you increase the mass of the reactants.
none of the above

For the following balanced reaction, which of the following is a gas?

2 Na(l) + Cl2(g) ? 2 NaCl(s)
Na
Correct Answer
Cl2
Cl
You Answered
NaCl

What is the formula mass of a molecule of c6h12o6?
Correct Answer
180 amu
24 amu
29 amu
You Answered
168 amu

What is the mass of one mole of H2?
Correct Answer
2 g
1 g
20 g
You Answered
6.022 × 1023 g

There are 1000 liters in 1 cubic meter and 1000 grams in 1 kilogram. How many grams of air are there in 0.01liter of air? (Assume a density of 1.25 kg/L.)
0.00125 gram
0.125 gram
You Answered
1.25 grams
Correct Answer
12.5 grams

If it takes energy to break bonds and you gain energy in the formation of bonds, how can some reactions be exothermic while others are endothermic?
Correct!
It is the total amount of energy that matters. Sometimes some bonds are stronger than others and so you gain or lose energy when you form them.
It is the total number of bonds that matters. Sometimes you create more bonds than you break and since all bonds have same amount of energy you gain or lose energy depending on the number of bonds.
Some reactants have more energetic bonds than others and they will always release energy.
Some products have more energy than others and they always require energy to be formed.

In a chemical reaction, the bonds being formed are ________.
the same as the ones broken
Correct!
different from the ones broken
more energetic than the ones broken
less energetic than the ones broken

In a chemical equation the coefficients ________.
of the reactants should always sum up to those of the products
appear as subscripts
Correct!
appear before the chemical formulas
Two of the above are correct.

What is the number of moles of H2O produced if you combust one mole of CH4 according to the following balanced equation?

CH4 + 2 O2 ? CO2 + 2 H2O
8 moles
6 moles
4 moles
Correct!
2 moles

If it takes three golf balls to equal the mass of one tennis ball, what mass of tennis balls do you need to equal the number of golf balls in one kilogram of golf balls?
Correct!
1/3 of a kg
30 kg
1 kg
3 kg

How many grams of water, H2O, can be produced by the reaction of 8 grams of oxygen, O2, and 8 grams of hydrogen, H2?
16 grams
10 grams
Correct!
9 grams
8 grams

An international group of zookeepers with successful breeding programs made the following animal exchanges last year. Using the same bartering system, how many anteaters can a zoo obtain in exchange for 4 oryxes?

3 oryxes = 1 tiger 2 flamingos = 1 anteater
1 camel = 6 anteaters 5 lemurs = 1 rhino
1 rhino = 4 monkeys 3 lemurs = 1 camel
3 monkeys = 1 tiger 1 rhino = 4 oryxes
6 anteaters
Correct!
10 anteaters
15 anteaters
20 anteaters
30 anteaters

A tiny crystal of sodium chloride contains 5,000,000 sodium ions and 5,000,000 chloride ions. The correct formula for sodium chloride is:
Correct!
NaCl
Na5Cl5
Na50Cl50
It could be any of the above.
None of the above

Which of these is an ionic compound?
Correct!
AlCl3
H2O
SiO2
IBr
S8

When properly balanced, what are the correct coefficients for the reaction : H2 + O2 ? H20 ?
1,1,1
1,1/2,1
1,2,1
Correct!
2,1,2
10,5,10

Using the old English measurements of volume listed, determine the number of noggins in one butt.

1 gill = 1 noggin 1 butt = 2 hogsheads
1 kilderkin = 2 firkins 1 firkin = 9 gallons
1 hogshead = 52.458 gallons 1 peck = 64 noggins
1 peck = 2 gallons
104.92 noggins
128.00 noggins
209.83 noggins
1678.7 noggins
Correct!
3357.3 noggins

Which of these is the correct SUM of the coefficients when the equation is balanced?

__ CaCl2(aq) + __ K2CO3(aq) ? __ KCl(aq) + __ CaCO3(s)
2
4
Correct!
5
8
10

How many moles of oxygen gas will react with 6.2 moles of aluminum?

4Al(s) + 3O2(g) ? 2Al2O3(s)
0.12 moles
1.55 moles
2.4 moles
Correct!
4.65 moles
8.27 moles

Which of these is not a covalent compound?
H2O
TeCl4
XeF4
C2H2
Correct!
AlCl3

What is the coefficient in front of oxygen (O2) when the equation is balanced?

__ C3H8 + __ O2 ? __ CO2 + __ H2O
2
3
4
Correct!
5
10

Which of these is the correct formula for potassium phosphate?
KPO4
Correct!
K3PO4
K(PO4)3
K2(PO4)3
K3P

Automotive air bags inflate when a sample of NaN3 (molar mass = 65 g/mol) is rapidly decomposed. What mass of NaN3 is required to produce 368 L of nitrogen gas (molar mass = 28 g/mol) with a density of 1.25 g/L?

2NaN3(s) ? 2Na(s) + 3N2(g)
228 g
Correct Answer
712 g
1709 g
You Answered
2136 g
3203 g

Barium fluoride is often used in glass manufacturing. Which of these is the correct formula and bonding type for barium fluoride?
BaF, ionic
BaF, covalent
Correct!
BaF2, ionic
BaF2, covalent
Ba2F, ionic

Which of these is the correct name for Ca(OH)2?
calcium carbonate
calcium oxide
calcium dihydride
calcium oxygen hydride
Correct!
calcium hydroxide

How many hydrogen atoms are in 25.6 grams of sucrose, (C12H22O11)?
1.647 atoms
2.6 × 1023 atoms
4.51 × 1022 atoms
6.02 × 1023 atoms
Correct!
9.92 × 1023 atoms

What is the coefficient in front of HF when the equation is balanced?

__ B2O3 + __ HF ? __ BF3 + __ H2O
1
2
3
5
Correct!
6

How many moles of calcium atoms are 2.5 moles of calcium carbonate, CaCO3?
1 mole
1.25 moles
Correct!
2.5 moles
5.0 moles
100 moles

How many grams are in 2.35 moles of calcium carbonate, CaCO3?
0.01175 grams
0.0235 grams
0.0588 grams
107 grams
Correct!
235 grams

An international group of zookeepers with successful breeding programs made the following animal exchanges last year. Using the same bartering system, how many monkeys can a zoo obtain in exchange for 10 camels?

3 oryxes = 1 tiger
2 flamingos = 1 anteater
1 camel = 6 anteaters 5 lemurs = 1 rhino
1 rhino = 4 monkeys 3 lemurs = 1 camel
3 monkeys = 1 tiger 1 rhino = 4 oryxes
6 monkeys
12 monkeys
15 monkeys
Correct!
24 monkeys
30 monkeys

What is the molecular weight of PCl3?
66.5 amu
106.5 amu
Correct!
137.5 amu
180 amu
360 amu

What is the molecular weight of cholesterol, C27H46O?
194 amu
208 amu
224 amu
180 amu
Correct!
386 amu

Are the chemical reactions that take place in a disposable battery exothermic or endothermic? Is the reaction going on in a rechargeable battery while it is recharging exothermic or endothermic?
An operating disposable battery is driven by endothermic reaction, while a recharging rechargeable battery is also driven by endothermic reactions.
Correct!
An operating disposable battery is driven by exothermic reaction, while a recharging rechargeable battery is driven by endothermic reactions.
An operating disposable battery is driven by endothermic reaction, while a recharging rechargeable battery is driven by exothermic reactions.
An operating disposable battery is driven by exothermic reaction, while a recharging rechargeable battery is also driven by exothermic reactions.

What is the number of grams of CO2 produced if you combust 0.50 mole of CH4 according to the following balanced equation?

CH4 + 2 O2 ? CO2 + 2 H2O
Correct!
22 g
10 g
44 g
32 g

A friend argues that if mass were really conserved he would never need to refill his gas tank. What explanation do you offer your friend?
The atoms (mass) of gasoline are converted into energy by the engine according to E = mc^2 ,!.
The Law of Conservation of Mass does not apply to reactions involving combustion or explosion of matter.
Correct!
The atoms (mass) of gasoline are converted into exhaust fumes.
The oil companies make gasoline in a way that it gets used up so that we are always required to replenish it.

How does a catalyst increase the rate of a reaction?
Correct!
It lowers the activation energy.
It is neither created nor consumed in a reaction.
It has nothing to do with the rate of reaction.
It increases the energy difference between the reactants and products.

Which has more atoms: 64.058 g of sulfur dioxide, SO2 (64.058 amu), or 72.922 g of hydrogen chloride, HCl (36.461 amu)?
64.058 g of SO2 has more atoms than 72.922 g of HCl
Correct!
72.922 g of HCl has more atoms than 64.058 g of SO2
72.922 g of HCl and 64.058 g of SO2 have about the same number atoms.
Not enough information is given.

If it takes three carbon atoms to equal the mass of one chlorine atom, what mass of chlorine do you need to equal the number of atoms in one kilogram of carbon?
Correct!
1/3 of a kg
30 kg
1 kg
3 kg
6 kg
Answer: A
Diff: 1
Learning Obj: 9.2
Global Obj: G-4

What is an exothermic reaction?
It is a reaction that requires heat as a reactant.
It is a reaction where the products have more energy than the reactants.
It is a reaction where there is a net adsorption of energy from a reaction.
all of the above
Correct!
none of the above

According to the following balanced chemical equation, if you want to generate two moles of H2O, how many moles of O2 do you need?

2 H2 + O2 ? 2 H2O
Correct Answer
1
2
1/2
4
You Answered
6.022 × 1023

What is the formula mass of a molecule of CO2?
Correct!
44 amu
56 amu
58.9 amu
118 amu

What is the formula mass of a molecule of C6H12O6?
Correct!
180 amu
24 amu
29 amu
168 amu

Which of the following has the greatest number of particles?
1 mole of Na
22.990 g of Na
1 mole of Be
9.012 g of Be
Correct!
All are the same.

Why might increasing the temperature alter the rate of a chemical reaction?
Correct Answer
The molecules will have a higher kinetic energy and bump into one another harder.
You Answered
The molecules are less reactive at higher temperatures.
The molecules will more likely combine with other atoms at high temperature to save space.
The density decreases as a function of temperature and this leads to an increase in volume which drops the rate of reaction.
none of the above

How many grams of water, H2O, can be produced by the reaction of 8 grams of oxygen, O2, and 8 grams of hydrogen, H2?
16 grams
10 grams
Correct!
9 grams
8 grams

What is the mass of an oxygen atom, O, in atomic mass units?
12 amu
Correct!
16 amu
18 amu
32 amu

How many grams of water, H2O, can be produced from the reaction of 25.0 grams of hydrogen, H2, and 225 grams of oxygen, O2?
You Answered
250 grams
Correct Answer
225 grams
200 grams
25 grams

Why is heat often added to chemical reactions performed in the laboratory?
to allow a greater number of reactants to pass over the activation energy
to increase the rate at which reactant collide
to compensate for the natural tendency of energy to disperse
Correct!
all of the above

Which of the following is a correctly balanced equation?
Correct!
P4 + 6 H2 ? 4 PH3
1 P4 + 6 H2 ? 4 PH3
0 P4 + 6 H2 ? 4 PH3
P4 + 12 H2 ? 8 PH3
P4 + 3 H2 ? PH3

What is the mass of one mole of H2?
Correct!
2 g
1 g
20 g
6.022 × 1023 g

Seven grams of nitrogen, N2, (N, atomic mass 14 amu) contains ________.
1 mole of nitrogen atoms
Correct!
0.5 moles of nitrogen atoms
0.25 moles of nitrogen atoms
Not enough information is given

Which of these is the correct name for MgCl2?
Correct!
magnesium chloride
magnesium chlorine
magnesium trichloride
magnesium monochlorine
monomagnesium trichloride

Which of these is the correct name for Li2SO4?
lithium sulfide
dilithium sulfide
dilithium sulfate
Correct!
lithium sulfate
dilithium tetrasulfide

Which of these is the correct name for Ca(OH)2?
calcium carbonate
calcium oxide
calcium dihydride
calcium oxygen hydride
Correct!
calcium hydroxide

Metals tend to ____ electrons and form ions with a ____ charge?
Correct!
lose, positive
lose, negative
gain, positive
gain, negative
lose , zero

Which of these is the correct formula for aluminum oxide?
Al2O2
Correct!
Al2O3
AlO
Al3O2
AlO2

How many grams of methanol (CH3OH) are produced when 5.00 kg of H2 reacts with excess carbon monoxide?

CO + 2H2 ? CH3OH
40 g
80 g
320 g
640 g
Correct!
40,000 g

Calculate the number of oxygen atoms in 45.0 g of Co2(SO4)3 (molar mass =405.8 g/mole).
Correct!
8.01 × 1023 atoms
2.67 × 1023 atoms
12.0 atoms
6.68 × 1022 atoms
1.07 × 1024 atoms

Why is the equation incorrect?

Mg3 + N2 ? Mg3N2
The equation is not balanced.
The coefficient of N2 is incorrect.
The valence of the nitride ion is incorrect.
Correct!
Some of the subscripts are incorrectly used.
The valance of the magnesium ion is incorrect.

How many moles carbon atoms are in 5 moles of ethanol, CH3CH2OH?
2.5 mole
5 moles
Correct!
10 moles
30 moles
120 moles

How many moles of oxygen atoms are in a 0.6163 grams of niacin, C6H5NO2?
5.14 × 10?2 moles
3.00 × 10?2 moles
Correct!
1.00 × 10?2 moles
5.01 × 10?3 moles
8.56 × 10?3 moles

Which of the following does not contain the same number of chlorine atoms as 60 CCl4 molecules?
240 HCl molecules
120 chlorine molecules
40 SCl6 molecules
80 CFCl3 molecules
Correct!
60 CHCl3 molecules

How many moles hydrogen atoms are in 3 moles of codeine, C18H21NO3?
3 mole
21 moles
36 moles
54 moles
Correct!
63 moles

Nonmetals tend to ____ electrons and form ions with a ____ charge?
lose, positive
lose, negative
gain, positive
Correct!
gain, negative
lose , zero

Using the old English measurements of volume listed, determine the number of hogsheads in five kilderkins.

1 gill = 1 noggin 1 butt = 2 hogsheads
1 kilderkin = 2 firkins 1 firkin = 9 gallons
1 hogshead = 52.458 gallons 1 peck = 64 noggins
1 peck = 2 gallons
Correct!
1.72 hogsheads
2.91 hogsheads
90 hogsheads
4,721 hogsheads
42,489 hogsheads

Which is of these is the correct ratio of sulfur to oxygen in SO2?
Correct!
1 sulfur: 2 oxygen
2 sulfur: 1 oxygen
2 sulfur: 2 oxygen
2 sulfur: 3 oxygen
1 sulfur: 3 oxygen

Which of these substances is a compound?
Na
You Answered
Cl2
Pb
Correct Answer
NO
H2

How many moles of caffeine are in 1.250 kg sample, C8H10N4O2?
6.4 × 10?6 moles
0.006 moles
0.008 moles
Correct!
6.44 moles
8.56 moles

What is the number of molecules of O2 consumed if you combust one mole of CH4 according to the following balanced equation?

CH4 + 2 O2 ? CO2 + 2 H2O
1 molecule
2 molecules
6.022 × 1023 molecules
Correct!
1.204 × 1024 molecules

Given that the bond energy of N2 is 946 kJ/mole, the bond energy of O2 is 498 kJ/mole and the NO bond energy is 631 kJ/mole, how much energy is required to react 1 mole of nitrogen molecules according to the following reaction?

N2 + O2 ? 2 NO
Correct Answer
182 kJ
-182 kJ
You Answered
813 kJ
-813 kJ

What is an endothermic reaction?
It is a reaction that requires heat as a reactant.
It is a reaction where the products have more energy than the reactants.
It is a reaction where there is a net adsorption of energy from a reaction.
Correct!
all of the above

How does a catalyst increase the rate of a reaction?
Correct!
It lowers the activation energy.
It is neither created nor consumed in a reaction.
It has nothing to do with the rate of reaction.
It increases the energy difference between the reactants and products.

How many grams of water can be formed from the reaction between 10 grams of oxygen and 1 gram of hydrogen?
11 grams of water are formed since mass must be conserved.
10 grams of water are formed since you can’t get a greater mass of water produced than oxygen reacting.
Correct!
9 grams of water are formed because oxygen and hydrogen react in an 8:1 ratio.
No water is formed because there is insufficient hydrogen to react with the oxygen.

How many grams of water, H2O, can be produced from the reaction of 25.0 grams of hydrogen, H2, and 225 grams of oxygen, O2?
250 grams
Correct!
225 grams
200 grams
25 grams

What happens to the entropy of a system as the components of the system are introduced to a larger number of possible arrangements, such as when liquid water transforms into water vapor?
The entropy decreases because there are less ways in which the energy can disperse.
Correct!
The entropy increases because there are more ways in which the energy can disperse.
The entropy of a system is independent of introducing the components of the system to a larger number of possible arrangements.
The entropy of a system is solely dependent upon the amount of material undergoing reaction.

Bond energies increase in going from C-N (lowest) to C-O to C-F (highest). Explain this trend based upon the atomic sizes of these atoms as deduced from their positions in the periodic table.
In going from nitrogen to oxygen to fluorine the atoms get larger. This means a greater nuclear charge, which translates into stronger chemical bonds.
In going from nitrogen to oxygen to fluorine the atoms get smaller. This means a greater nuclear charge, which translates into stronger chemical bonds.
In going from nitrogen to oxygen to fluorine the atoms get larger. This means that the bonding atoms are farther apart, which translates into a greater bond energy.
Correct!
In going from nitrogen to oxygen to fluorine the atoms get smaller. This means that the bonding atoms are closer together, which translates into a greater bond energy.

Chlorine is put into the atmosphere by volcanoes in the form of hydrogen chloride, HCl, but this form of chlorine does not remain in the atmosphere for very long. Why?
The hydrogen chloride is destroyed by ultraviolet rays.
Correct!
The hydrogen chloride is washed away by atmospheric moisture.
The hydrogen chloride reacts with atmospheric carbon dioxide.
The hydrogen chloride degenerates into hydrogen and chlorine

The relative mass of carbon is 3/8 that of an oxygen molecule. How many grams of carbon are needed to have the same number of particles as found in 32 grams of oxygen molecules?
Correct!
12 g
32 g
3 g
8 g

For the following balanced reaction, which of the following is a gas?

2 Na(l) + Cl2(g) ? 2 NaCl(s)
Na
Correct!
Cl2
Cl
NaCl

A 1.00 carat pure diamond has a mass of 0.20 grams. How many carbon atoms are there within this diamond?
6.02:times10^{23}
2.0:times10^{23}
1.0:times10^{23}
Correct!
1.0:times10^{22}

For the following balanced equation, which has the highest coefficient?

4 H2 + 2 C ? 2 CH4
Correct!
H2
C
CH4
H4

What is the activation energy?
Correct!
the minimum amount of energy to break the bonds in reactants
the amount of energy required to activate a phase change
the energy difference between the reactants and the products
the amount of energy required to separate reactants from the products

Why might increasing the concentration of a set of reactants increase the rate of reaction?
Correct!
You have increased the chances that any two reactant molecules will collide and react.
You have increased the ratio of reactants to products.
The concentration of reactants is unrelated to the rate of reaction.
The rate of reaction depends only on the mass of the atoms and therefore increases as you increase the mass of the reactants.
none of the above

There are 1000 liters in 1 cubic meter and 1000 grams in 1 kilogram. How many grams of air are there in 0.01liter of air? (Assume a density of 1.25 kg/L.)
0.00125 gram
0.125 gram
1.25 grams
Correct!
12.5 grams

How many bonds (in total) between nitrogen and hydrogen are formed if you react nitrogen with hydrogen according to the following reaction?

N2 + 3H2 ? 2 NH3
1
4
3
Correct!
6
8

If the pH of a solution is 10, what is the hydronium ion concentration?
1 × 1010 M
-10 M
10 M
Correct!
1 × 10-10 M

According to the following reaction, which molecule is acting as an acid?

H2O + H2SO4 ? H3O+ + HSO4-
H3O+
none of the above
H2O
Correct!
H2SO4
HSO4-

According to the following reaction, which molecule is acting as a base?

H3O+ + HSO4- ? H2O + H2SO4
H3O+
Correct!
HSO4-
none of the above
H2SO4
H2O

Can an acid and a base react to form an acid?
Yes and No. The reaction can only occur if the substances reacting are true acids and bases.
Correct!
Yes. An acid and a base can react to form an acid if the acid is a strong acid and the base is a weak base.
No. Acids always react with bases to form salts.
Yes and No. The reaction can only occur if the reactants are organic/carboxylic acids and organic bases.

A weak acid is added to a concentrated solution of hydrochloric acid. Does the solution become more or less acidic?
Correct!
Less acidic, since the solution becomes more dilute with a less concentrated solution of hydronium ions being added to the solution.
More acidic, since there are more hydronium ions being added to the solution.
No change in acidity, since the concentration of the hydrochloric acid is too high to be changed by the weak solution.
Less acidic since the concentration of hydroxide ions will increase.

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ? H2PO4- + H3O+
both
base
neither
Correct!
acid

According to the following reaction, which molecule is acting as a base?

OH- + NH4+ ? H2O + NH3
none of the above
Correct!
OH-
H2O
NH4+
NH3

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ? H2PO4- + H3O+
both
neither
Correct!
base
acid

The hydroxide ion, HO-, is a ________.
Correct!
polyatomic ion
proton donator
very strong acid
unique form of water

Which of the following statements about buffers is untrue?
A salt from the reaction of a strong acid and a strong base can be used to make a buffer.
Addition of small amounts of base to a buffer changes the pH.
Correct!
The pH of a buffer solution cannot change.
None of the above are true.
Addition of small amounts of acid to a buffer changes the pH.

An acid and a base react to form a salt, which consists of positive and negative ions. Which forms the positive ions: the acid or the base? Which forms the negative ions?
all of the above
Correct!
The acid forms the negative ion, the base forms the positive ion.
Because different substances can act as an acid or a base, it depends on the substance you begin with.
The acid forms the positive ion, the base forms the negative ion.

According to the following reaction, which molecule is acting as a base?

H2O + H2SO4 ? H3O+ + HSO4-
HSO4-
Correct!
H2O
H3O+
none of the above
H2SO4

Water is formed from the reaction of an acid and a base. Why is it not classified as a salt?
The attraction between the two ions in water molecules are too strong.
By definition, a salt must be able to dissolve in water, so water itself cannot be called a salt.
Not all acid base reactions produce a salt, as in the case with the formation of water.
Correct!
A salt is an ionic compound, whereas water is a covalent compound.

According to the following reaction, which molecule is acting as an acid?

H3O+ + HSO4- ? H2O + H2SO4
none of the above
Correct!
H3O+
H2O
HSO4-
H2SO4

What best describes what happens when an acid such as HCl is mixed with water?
A hydroxide ion from the water is transferred to the HCl molecule to form a proton and hydronium ion.
Correct!
The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion.
HCl is not an acid.
none of the above
A proton from the chlorine nucleus is ejected and captured by a water molecule to form a negatively charged HCl and a new hydronium ion.

According to the following reaction, which molecule is acting as an acid?

H2O + NH3 ? OH- + NH4+
NH3
Correct!
H2O
none of the above
NH4+
OH-

According to the following reaction, which molecule is acting as an acid?

OH- + NH4+ ? H2O + NH3
Correct!
NH4+
H2O
none of the above
NH3
OH-

Which of the following statements is not true about a neutralization reaction?
None of the above are true.
One molecule of acid neutralizes one molecule of base.
Correct!
Water is always formed in a neutralization reaction.
A neutralization is the reaction of a hydroxide ion with a proton.
All of the above are true.

Which of the following solutions is the most acidic?
Correct!
a solution with a pH = 5
a solution with a pH = 12
All of the solutions are basic.
a solution with a pH = 13
a solution with a pH = 14

How do you make a proton out of a hydrogen atom?
let the hydrogen atoms undergo fusion
remove an electron from a helium nucleus
let the hydrogen atoms combine to form a hydrogen molecule and eject an electron
Correct!
remove an electron from a hydrogen atom

As the pH increases, the hydroxide ion concentration ________.
goes down
starts to affect the H+ concentration
Correct!
gets larger
stays constant
starts to decrease because it is reacting with the excess hydronium ions

What is the main characteristic of a strong base?
It readily accepts an acidic proton.
It is corrosive.
Correct!
It is completely dissociated in water.
It will damage your skin.

The hydronium ion, H3O+, is a ________.
very strong base
Correct!
polyatomic ion
unique form of water
proton acceptor

A strong acid tends ________.
Correct!
all of the above
to form negatively charged ions when dissolved in water
to be strongly polar
to form positively charged ions when dissolved in water

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ? H2PO4- + H3O+
acid
Correct!
base
neither
both

For the following acid-base reaction, identify what compound is formed in the space marked.

HNO3 + KOH ? ???? + H2O
KNO2
none of the above
Correct!
KNO3
H3ONO3
KOH2NO3

Along with the pH scale, there is the pOH scale, which indicates the level of “basicity” in a solution. Accordingly, pOH = -log[OH-]. What is the sum of the pH and the pOH of a solution always equal to?
Correct!
the negative of the product of the hydronium and hydroxide ions
It is not constant because it depends on the acid/base solution in question.
The sum would equal 7, since that would be neutral for pH and pOH.
the negative log of OH, which is 14

According to the following reaction, which molecule is acting as a base?

H2O + NH3 ? OH- + NH4+
none of the above
H2O
OH-
Correct!
NH3
NH4+

If the pH of a solution is 10, what is the hydroxide ion concentration?
Correct!
1 × 10-4 M
4 M
-14 M
14 M

How does a base like NH3 raise the hydroxide ion concentration?
The NH3 molecule is not a base and therefore does not change the hydroxide ion concentration.
Correct!
The NH3 molecule removes a proton from a water molecule.
The NH3 molecule releases reacts with a hydronium molecule, altering the number of hydroxide ions in the process.
The NH3 molecule releases a proton that has to be neutralized by a water molecule.

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ? H2PO4- + H3O+
both
Correct!
acid
base
none of the above
neither

What happens to the pH of an acidic solution as water is added?
The pH is not influenced by the addition of water.
Correct!
The pH will increase as the solution becomes more dilute.
The pH will decrease as the solution becomes more dilute.
The pH will decrease since more hydronium ions are produced from the water.

If the pH of a solution was 7 and you were to increase the hydronium ion concentration 1000x, what would the pH be?
4 M
7,000 M
1 × 10-4 M
10
Correct!
4

For the following acid-base reaction, identify what compound is formed in the space marked.

HCl + KOH ? ???? + H2O
Correct!
KCl
KOH2
KOH2Cl
none of the above
H3OCl

As the hydronium ion concentration increases, the pH ________.
stays constant
gets larger
Correct!
goes down
starts to alter the chemical properties of the water molecules
starts to affect the OH- concentration

What is the main characteristic of a strong acid?
Correct!
It is completely dissociated in water.
It readily gives up its proton to a base.
It is corrosive.
It will damage your skin.

If you had a 1 M solution of a weak acid what would be its pH?
1
6
8
7
Correct!
it would depend on the acid

What is an acid?
anything that accepts hydrogen atoms
anything that donates hydronium ions
anything that dissolves metal
Correct!
anything that donates hydrogen ions
anything that donates hydrogen atoms

Carbon dioxide reacts with water to form ________.
sodium bicarbonate
hydrated carbon
Correct!
carbonic acid
carbon dioxide and water

For the following acid-base reaction, identify what is formed in the space marked.

H2SO4 + KOH ? KHSO4 + ???
Correct!
H2O
KOH2SO4
H3OSO4
K2SO4
none of the above

For the following acid-base reaction, identify which salt is formed.

HCl + NaOH ? ???? + H2O
H3OCl
NaOH2
NaOH2Cl
none of the above
Correct!
NaCl

For the following acid-base reaction, identify what is formed in the space marked.

HF + KOH ? ???? + H2O
KOH2
KOH2F
H3OF
none of the above
Correct!
KF

Does the hydride ion, H?, tend to behave as an acid or a base?
Hydride ion’s makeup consists of one proton and two electrons. As such, its tendency is to form neutral hydrogen gas, , and therefore is neither acidic nor basic, but neutral.
Although the hydride ion has two electrons, they do not pair together. Thus, the hydride ion is incapable of acting as a Lewis base and therefore tends to behave as an acid.
Hydride ion is unstable and re-reacts with water to form an acid in the form of the hydronium ion, H3O?.
Correct!
Hydride ion has a pair of electrons and acts like a Lewis base since it has a strong tendency to lend or donate that electron pair.

What is a base?
anything that donates a hydroxide ion
anything that can be used to clean drains
anything with a bitter taste
Correct!
anything that accepts a hydrogen ion
anything that accepts a hydroxide ion

A buffer solution can neutralize ________.
with no change in pH
salt solutions
Correct!
strong acids and bases
All of the above.
only weak acids and bases