DAT General Chemistry

What is the shape of a p orbital?
figure 8
If you change the amount of neutrons, what is the yield?
A different isotope
If you change the electrons, what is the yield?
A new ion
If you change the protons, what is the yield?
A different element

True or False:

 

Molecules in the same period react the same.

False. Groups
***On the DAT anytime you see a reactivity question with H2O, the answer is an Alkali metal
Question is the answer
Which group is the alkaline earth metals
group 2

True or False:

 

The noble gases are extremely reactive

false
Every shell has ____ orbitals (equation)
n^2
What is the equation for the maximum electrons per shell
2n^2
In an electron configuration, what makes the configuration most stable.
Having the shell full or 1/2 full
What is paramagnetic?
Unpaired electrons (odd # e-)
What is Diamagnetic?
Slight deflection from magnetic field (all e-‘s are paired)
What symbol denotes the Azimuthal subshell?
l
What type of force overpowers electrostatic repulsion?
Strong Nuclear Force
What particles are considered the heaviest?
Alpha particles
Which particle has the least penetrating power?
Alpha particles
Which nuclear particles are the lightest and have the most penetrating power?
Gamma Rays
What are the 2 checks that are needed for a nucleus to be stable?

Even # protons and/or neutrons

N/z ration = 1

Which gives more energy, nuclear reactions or chemical reactions?
Nuclear Reactions (much more powerful)
Where is the e- located during electron capture?
The reactants
In electron emission, where is the electron located?
The products
In alpha-emission, where is the alpha particle located?
The products
What type of atoms are likely to undergo alpha decay?
z;83 large atoms
What is the only type of decay which loses mass number?
Alpha-decay
Why is beta decay used?
n/z ratio is too high
Why are positron emission and electron capture used?
n/z ratio is too low
What is a nucleon?
Anything living in the nucleus

True or False:

;

1/2 life is constant in 1st order rxns

True
What order rxn is always seen in spontaneous nuclear decay
1st order
What decides if something has a higher nuclear binding energy?
The closer it is to (56/26) Fe
What is the periodic trend for atomic radius/size increase?
Down the table, to the LEFT

Which radius is smaller and why?

;

Mg or Mg^2+

Mg^2+ because cations have a smaller radius than there neutral counterpart

Which has a smaller radius and why?

;

S or S^2-

S because Anions have a larger radius than there neutral counterpart
What is the Zeff equal to?
The # of valence e-‘s
What should you look for if a question asks which species will have an ionic radius that is smaller than the atomic radius?
LOOK FOR A METAL because metals love to form cations
If a question asks which species will have an ionic radius that is larger than the atomic radius, what should you look for and why?
A non-metal because non-metals love to form anions
What does an isoelectronic series mean?
All atoms have same # e-‘s
What is the trend for highest 1st ionization energy?
Up and to the left
What is electron affinity?
Change in energy by gaining an e-
What is electron affinity associated with?
Reduction
Is electron affinity typically endothermic or exothermic?
Exothermic
What is the periodic trend for electron affinity?
Left to right.
What two groups are exceptions to the electron affinity trend?
Group containing N and group containing Be
How are electronegativity and polarity related?
The bigger the difference in electronegativity, the more polar the bond.

True or False:

;

Solid compound are good electrical conductors?

False
What do compounds with ionic bonding typically form?
Crystals

True or False:

;

Compounds with Ionic bonding have Very High MP but low BP

False: High MP and BP
What are the 2 types of covalent bondings?
Covalent networks and molecular compounds
What is the relative BP and MP for a covalent network?
High for both
What is the relative MP and BP for molecular compounds?
Low for both
What is the relative strength for ionic and covalent bonds?
Very strong

True or False:

;

Compounds with metallic bonding are electrically and thermally conductive

true
In a coordinate covalent bond, what determines a lewis acid vs. lewis base

Lewis base- donates both electrons

Lewis Acid- does not contribute electrons to the bond

What is the bond angle for a linear molecular geometry
180 degrees
How many e- domains are in a linear molecular geometry
2 e- domains
What is the bond angle for trigonal planar?
120 degrees
How many e- domains are in trigonal planar molecular geometry
3 e- domains
What is the bond angle for tetrahedrals?
109.5 degrees
How many domains are in tetrahedrals?
4 e- domains
What are the bond angles for trigonal bipyramidal geometry?
90 120 and 180 degrees depending on which bonds are in question
How many e- domains are in trigonal bipyramidal?
5 e- domains
What is the bond angle for an octahedral?
90 degres
How many e- domains are in an octahedral?
6 e- domains
What effect do lone pairs have on the bond angle?
Make them slightly smaller
How can a compound containing polar bonds be non-polar?
If the polar bonds cancel each other out
What type of molecules do dipole-dipole interactions occur?
Polar molecules
What is the relation between polarity and dipole-dipole forces?
More polar = larger dipole-dipole
Are Ionic and Covalent bonds inter or Intra molecular forces?
Intra
What type of intermolecular forces do non-polar molecules have?
Only london dispersion forces
What is ion dipole attraction?
molecule completely charged binds to something partially charged

Rank the following in strength

;

Dipole-dipole, hydrogen bonding, ion-dipole, london dispersion

Hydrogen bonding, ion-dipole, dipole-dipole, london dispersion
How are IMF’s related to BP, MP, Viscosity, Surface Tension, and Vapor Pressure

Higher IMF’s = higher BP, MP, Viscosity, and Surface tension.

;

Higher IMF’s = lower vapor pressure

If all molecules are non-polar how do you distinguish between the strongest and weakest IMF strength?
The size of the molecule has the largest IMF strength
How does an increase in temperature affect the VP?
it increases the VP
When you lower the pressure how does this affect a molecules boiling point?
It lowers the BP
What are the two major assumptions for ideal gases?

1) Gas molecules have no volume

2) No IMF’s

What is Charles’s law?
Temp increase leads to volume increase
In boyles law, how is volume related to pressure?
Inversely proportional
What is the partial pressure law equation?
Pa = Xa * Ptotal
How is KEavg related to temperature?
KEavg does NOT change with temperature
What is the equation used for Graham’s Law of Effusion?
R2/R1 = sqrt(molar mass1/molar mass 2)
What gas escapes quicker according to Graham’s Law of Effusion?
The lighter gas
What are the 7 diatomic atoms?
N, H, F, O, I, Cl, Br
How is a supersaturated solution made possible?
By heating
What is the equation for molality?
mol solute/ Kg solvent
What is the mol fraction equation?
mol A/ tot mol
What are the 2 important solubility rules that need to be known?

1) All group 1 metals, NO3-, NH4+, ClO4-, C2H3O2- salts are SOLUBLE

2) Most Ag+, Pb 2+, Hg2 2+ salts are INSOLUBLE

Are solids more soluble at higher or lower temperatures?
Higher
Are gases more or less soluble at higher temperatures?
Less Soluble
What is the relationship between gas and pressure?
Gases are more soluble at higher pressure
What is the equation for freezing point depression? When do you use it?

Delta T = -i*Kf*m

 

Use this when trying to figure out the new freezing point when a different solute is added

What is the equation for BP elevation?
Delta T = i*Kb*m
Why do impurities lower the freezing and melting points
Because it makes it more difficult to form crystal structures
What is the relationship between impurities and IMF’s?
impurities increase the amount of IMF’s
How do impurities affect the boiling point?
Impurities increase the boiling point
What is the Vant Hoff factor?
the amount of pieces a compound will split in to
What is the vant Hoff factor of Na2SO4?
3    2 Na and 1 SO4
What is the vant Hoff factor for a molecular compound?
1 because it doesn’t split
How do you calculate the highest BP between .1m NaCl, .08m Al(NO3)3, .2m CH3OH ?
Calculate the i*m and the highest number will have the highest boiling point
Which law do we use for vapor pressure depression?
Raoults Law
Why does VP lower with an increase in IMF’s?
Because more IMF’s make it harder for a molecule to escape, thus lower VP
What is osmotic pressure?
The amount of pressure needed to prevent H2O levels from rising
When do you use the vant Hoff factor in calculations?
;If the solute splits

What are the rate expressions for each of the reactants and products

;

2 NH3 —-> N2 + 3H2

Delta [N2]/delta t

Delta [H2]/ 3*delta t

Delta [NH3]/2*delta t

How does the concentration affect the rate of reaction in a 0th, 1st, or 2nd order reaction

0th- concentration has no effect

1st- concentration is directly proportional to rate

2nd- concentration is squared to get rate

Why do chemical reactions slow down over time?
Because the concentration decreases
What is the shortcut method to finding the rates of certain reactions?

Find the change in concentration and figure out how much it is multiplied by and set that as 2^x (if concentration is doubled 3^x if tripled). Then go to the rate and figure out the same thing. Set this value = to 2^x

 

2^x=4

Now solve for X and this will be the order for that concentration and plug it into the equation

How do you figure out the overall order of a reaction?
Sum the exponents
What is a unimolecular, bimolecular, and termolecular reaction

Unimolecular- 1 reactant molecule

Bimoleuclar- 2 reactant molecules

termolecular- 3 reactant molecules

How is collision frequency and temperature related?
increased temperature increases collision frequency
What is the equation for the Arrhenius equation?
K = Ae^-Ea/RT

True or False:

 

Temperature has no effect of the activation energy

True
How are Ea and K related?
As Ea increases, K decreases
What are 3 ways to increases the rate of rxn?
Increase temperature, Lower Ea, increase [ ] reactants
What are 2 ways to increase K? Does the [ ] have any effect?

Increase temperature, lower Ea.

 

[ ] has ZERO effect

If K >> 1 what is favored at equilibrium?
Products
If K <<1 what is favored at equilibrium?
Reactants
If K is ~1 what is favored at equilibrium?
Both products and reactants in equal amounts
What is an easy way to remember which way the reaction will shift when looking at the difference in K and Q?
Write K before Q and which ever direction the arrow points is the direction that the reaction will go.
By using K and Q, how can we tell if the reaction is at equilibrium?
If K = Q
What is the only way the we can change the value of a constant?
If we change the temperature
If you reverse a reaction, what happens to the reaction constant?
You inverse the reaction constant, NOT making it negative!
What effect do solids have with Le Chatliers principle?
NONE
If you increase the pressure of a reaction which way will the reaction shift?
To the side with the least amount of moles
If you decrease the volume, which way will the reaction shift?
To the side with the least amount of moles.
According to Le Chatliers Principle, if you increase the temperature is the endothermic or exothermic side favored?
Endothermic
If Kc= [H2O]/[O2], what will happen to Kc if you add a bunch of O2 and why?
Nothing will happen to Kc since it is a constant. However, it will simply be changed to Qc.
What is significant about the ion [ ]’s at Ksp?
They are the highest ion [ ]’s possible before the ion’s precipitate.
In a solubility-type reaction, if you add something that can complex with the products, which way will the reaction shift?
Right
What is the quick cheat for figuring out molar solubility problems and when does it NOT work?

This ONLY works if NO common ions are present.

 

Figure out how many ions of each atom that the compound will split into and set the # per atom as a coefficient and exponent. Then solve for X.

 

Ex) BiI3    Ksp= x*3x^3 = 27x^4

How would you go about solving this problem:

 

What is the solubility of AgCl in 0.1M HCl?

Ksp = 1.8*10^-10

1st, write the Ksp equation and add 0.1 to the common ion

Ksp = x * x+0.1

2nd, assume the x next to the 0.1 is negligible

1.8*10^-10 = x*0.1

3rd, solve for x

1.8*10^-10/0.1=x

x=1.8*10^-9

What is the definition of an Arrhenius base?
OH- is donor in H2O
What is the definition of an Arrhenius Acid?
H+ is donor only in H2O
What is a Bronsted-Lowry acid?
H+ is the donor PERIOD
What is a Bronsted-Lowry base?
H+ acceptor
What is a Lewis Acid?
e- acceptor
What is a Lewis base?
e- donor
What is a trick to remember the strong bases?
All of Group I and the larger Group II
What does it mean for something to be a strong acid?
It dissociates 100%
What are the 7 strong acids?
HCl, HBr, HI, HNO3, HClO4, HClO3, H2SO4
What is the trend for relative strength of a binary acid?
To the right and down the periodic table
What is the trend of relative strength of oxoacids?
More oxygen means more acidic
What is a heteroatom in an oxoacid?
Any atom other than oxygen
How is electronegativity related to the relative strength of an oxoacid?
The more electronegative heteroatom, the more acidic the oxoacid
What is needed in order to solve for the pH of a weak acid?
[ ] and Ka
What is the equation required to solve for the pH of a weak acid?
Ka = ([H+]*[A-])/[HA]
What is the equation required to solve for the pH of a weak base?
Kb = ([OH-]*[HA])/[A-]
Are acid base neutrilizations endothermic or exothermic?
Exothermic
How do Ka and Kb relate to acid and base strength, respectively?
larger Ka and Kb value mean a stronger acid or base
How does pKa or pKb relate to acid or base strength?
Larger pKa or pKb value means a weaker acid or base
If the value of Kw increases, what happens?
If Kw increases the value of the “neutral pH” decreases (becomes more acidic)
Which will release more heat, a strong acid w/ a strong base or, a strong acid with a weak base
strong acid w/ strong base
What are the negligible cations?
Group 1 and Group 2 cations
What is the relationship between charge and acidity?
The higher the positive charge, the more acidic
What are the negligible anions?
Those who are complements of a strong acid
How do basic salts become more soluble?
When you add an acid to the solution
When asked a question like, “Which of the following compounds is least dependent upon the pH of the solution,” what do you look for?
You look for the compound that is neutral
What are buffers made from?
Weak acids and their conjugate bases
Which equation would you use to calculate the pH of a buffer solution (name and actual equation)?

Henderson-Hasselback

 

pH = pKa + log [A-]/[HA]

If the pH of a compound is 3.2, what is the buffering capacity range?
2.2-4.2
What formula do you use to measure the comparative strengths of acidity?
10^x
When using the Henderson-Hasselback why do you use moles for the [A-] and [HA]?
Because the liters will eventually cancel eachother out so it is perfectly fine to use mols
For a strong acid, strong base titration, what pH will the equivalence point be at?
7
For a weak acid, strong base titration, what pH will the equivalence point be at?
pH > 7
For a strong acid, weak base titration, what pH will the equivalence point be at?
pH <7
If you have a weak acid, strong base titration, why is the pH greaker than 7?

Because the conjugate base that you form from the weak acid is an actual base and not a neutral salt. The DAT will word it like this, “The weak acid will undergo hydrolysis to form hydroxide”

 

NOT because a strong base is present vs. a stong acid!!

Why is the pH less than 7 in a strong acid, weak base titration?
Because the conjugate acid will dissociate and form H+ in to final solution
In a SA/SB titraiton curve, what does the initial line look like?
straight line
How do you solve for the concentration in a titration problem?
MOLARITYacid*VOLUMEacid = MOLARITYbase*VOLUMEbase
At the 1.2 equivalence point, what is pH equal to?
pKa
If the pKa is 4, what would make an effective buffer?
pka 3-5
What point on a titration curve will always give you the pKa?
The 1/2 equivalence point
What is the 1st law of thermodynamics?
energy is conserved
What is the 2nd law of thermodynamics
For a spontaneous process, entropy increases
What is the 3rd law of thermodynamics?
A perfect crystal at 0 kelvin has 0 entropy
What is the equation for the change in internal energy?

Delta E = q + w

 

OR

 

Delta E = q-P*delta V

If 100 J of heat was transferred from the system to the surrounding and 50 J of work was pperformed on the system. What is delta E?

-50 J

 

-100+50=-50

From the following equation, how can we tell that delta S is positive?

 

2C(s) + O2(g) —-> 2CO(g)

There is one mole of gas in the reactants vs. 2 moles of gas in the products
When a solid is going to a liquid and to a gas, what is the sign of delta S?
Positive
Can delta S for the system ever be negative, why or why not?
Yes, the system can be negative but the summation of the system and the universe must be positive
If delta S of the reaction is not given, how could you solve for it?
Delta S rxn = (Sigma(n*S products)) – (Sigma(n*S reactants)
What does it mean for something to be a state function?
It is independent of the pathway meaning it does not depend on the intermediates but ONLY the initial and final states
What are the two major NON state functions
q and w
Is breaking bonds endothermic or exothermic? Forming bonds?

Breaking- endothermic

Forming- exothermic

What is the equation for bond enthalpy?
Delta H rxn = Delta broken – Delta formed
What is the enthalpys of formation measuring?
The enthaply it takes to FORM the products
What 2 things classify a formation reaction?

1) 1 mole of product is being formed

2) Reactants are all elements in their standard state

What is the standard state of Carbon?
C(graphite)
What is the Delta H value of any element in their standard state?
0

Which of these values changes, if any:

 

Delta G

 

Delta G not

Delta G

 

Delta G not does not change ever

What is the equation used to solve for Delta G?

 

Delta G = Delta G not + RT * ln*Q
What is the equation to solve for Delta G not?
Delta G not = -RT*lnK
What is the equation used to solve for Delta G not of the entire reaction?
Delta G not reaction = DGnot products – DGnot reactiants

True or False:

 

When at a phase change temperature, the two phases are in equilibrium with one another?

True
Why does the universe prefer exothermic reactions?
Because it lowers the energy required in the universe and makes it more stable
How would you solve a free energy problem that is asking for temperature dependence?
Set delta G equal to zero and solve the rest
What is another name for the oxidant?
Oxidizing agent, the compound causing oxidation
What is another name for the reductant?
The reducing agent, the compound causing reduction
In a Galvanic cell, which electrode gets oxidized?
The anode
Which way does electricity flow in a galvanic cell?
Anode —–> Cathode
Are galvanic cells spontaneous or non-spontaneous? What is the Ecell (>or<0)?
Spontaneous Ecell>0
Does the galvanic cell produce or consume electricity?
Produce
What is the orientation of polarity of a galvanic cell? Electrolytic cell?

Galvanic- Anode – Cathode +

Electrolytic- Anode + Cathode –

Does a galvanic or electrolytic cell have a salt bridge?
Galvanic
In a Galvanic cell anode, where would you typically find the electrons in the 1/2 reaction?
Products
In a Galvanic cell cathode, where would you typically find the electrons of the 1/2 reaction?
The reactant
In a Galvanic cell, which electrode will gain mass?
+ electrode or Cathode
In a Galvanic cell, which electrode will lose mass?
The Anode or – electrode
In a galvanic cell, how to the salt ions move in the salt bridge and why?
Anions to anode and cations to cathode in order to keep neutrality in the solution
In a Galvanic cell, where do the electrons flow through, where do the ions flow through?

e- flows through the wire

ions flow through the salt bridge

What equation do you use to calculate the standard cell potentials (E not)?
E not = E not reduction+ E not oxidation
What is the standard potential of a hydrogen atom?
0
Does the amount of moles have any bearing on the standard potential?
NO
What is the non-standard cell potential equation?

E = E not – (.0592/n) * log Q

 

Q = [material in products]/[material in reactants]

How can you increase the standard cell potential?
Shift the reaction to the right
How can you decrease the standard cell potential?
Shift the reaction to the left
What are the 2 classifications for a reaction to be spontaneous?

1) The sum of the potentials is positive

2) One molecule is oxidized and one is reduced

In a spontaneous reaction what is the relative value of Delta G, Ecell, and K vs Q?

Delta G <0

Ecell>0

K>Q

In electrolysis, which electrode do anions and cations go to, respectively?

Anions- Anode

Cations- Cathode

What equation is required to solve electrolysis calculations?
(Amp*time(sec))/(n*F)=mol product
How can you tell if an element if in its “excitatory” state based off of its electron configuration?
Because it skips an entire shell if it is in its excitatory state

*Need periodic table*

 

What is the e- configuration for Cu+?

 

1s2 2s2 2p6 3s2 3p6 3d10

Which of the following is paramagnetic? Why?

 

Cl-, Ag, Cu+, Mg 2+

Ag because it has an unevenly filled electron configuration (unpaired e-)

Which of the following is diamagnetic? Why?

 

Cu+, Fe3+, Ca+

Cu+ because it does not have any unpaired electrons
What are the maximum amount of electrons possible in the 3rd shell?
2*3^2 = 18 

How many orbitals are in the 4th shell?

 

4^2 = 16

Which of the following is likely to be radioactive? Why?

 

Mg(24), O(16), Au(196), C(12)

 

(X) denotes isotope number

Au(196) because it is the only choice greater than z>83

Which of the following is likely to decay by alpha emission and why?

 

Ne(23), He(4), Ur(235), C(14)

Ur(235) because it fits z>83
What is the product of the gamma emission of (60)Co and Why?
(60)Co gamma emission doesn’t change protons or neutrons

Which is most likely to decay by beta emission? Why?

 

Ca(40), O(16), C(14), N(14)

C(14) because n/z is not equal to 1

What is the product of the alpha decay of (210)Po?

 

*Need Periodic Table*

(210)Po —-> (4)He + (206)X

 

X = Pb

What is the product of e- capture of (20)Na?
(0/1)e- + (20)Na —–> (20) Ne
Which route of decay converts a proton into a neutron?
Both positon emission and e- capture

Which of the following has the highest 1st ionization energy? Why?

 

Al, Si, P, S, Mg

 

*Need Periodic Table*

P

 

The exception to the trend is that group 5 is greater than group 6

Which of the following has an ionic radius smaller than its corresponding atomic radius?

 

N, Li, O, Cl

Li because Li is the only cation and cations have smaller ionic radii than atomic radii

Which of the following has the highest e- affinity?

 

O, N, C, F

F

Which of the following has the highest 2nd ionization energy? Why

 

Mg, Na, C, Be

Na because the highest 2nd ionization energy is the molecule with only one valence e-

Which of the following has the highest BP and why?

 

H2O, HOCH2CH2OH, Ar, NaCl, CH3OCH3

NaCl because it is the only ionic molecule

Highest BP? Why?

 

HOCH2CH2OH, CH3CH2OH, H2O, NaOH

NaOH because it is ionic

Highest BP? Why?

 

CH3OH, (CH3)2, CH3F, CH4

CH3OH because it has the most IMF’s

Highest VP?

 

Kr, Ar, Ne, He

He

Highest BP?

 

CH3OH, CH3CH2OH, CH3(CH2)F, CH3(CH2)2OH

CH3(CH2)2OH because it is the largest molecule with hydrogen bonding

Which of the following are exothermic and endothermic?

 

Vaporization, Condensation, Sublimation, Fusion

Condensation- exothermic

 

Vaporization, Sublimation, Fusion- endothermic

What is deposition?
From Gas to Solid
What is fusion?
From solid to liquid
Where/what is the triple point?
The point where all there phases meet on a phase diagram
Where/what is the critical point on a phase diagram? What does the critical point mean?
The furthest point to the right which denotes the point of supersaturation
How does a noble gas behave most ideally?
With increased temperature and decreased pressure

Which of the following has the highest KEavg at 25 degrees C?

 

CO2, Ar, F2, all the same

All the same because KEavg is the same for all compounds at the same temperature
When you have two different gases in a balloon, which will escape the fastest?
The lighter gas
At what rate will either O2 or H2 escape quicker? Which element escapes quicker? Which law is required to solve this problem?
sqrt(32/2) = 4 times quicker. H2 will escape quicker. We use Graham’s law to solve this problem

True or False:

 

The gas with the most IMF’s will behave most ideally?

False, exact opposite

Which of the following is most likely an ideal gas?

 

Ne, CO2, H2O, Xe

Ne, because it has the least amount of IMF’s and it is the lightest while still fulfilling the two major ideal assumptions
What increases the solubility of HCl in H2O? (2 things)
Decrease temperature, increase pressure

Which of the following increases BP the most? Why?

BaSO4, KCl, CH3OH, CaCl2

CaCl2 because it dissociates into the most ions
If Kf = 1.86 and the freezing point = -0.62, what is the molality?

-1.86 * m = -0.62

 

m = 0.33

Which of the following has the highest freezing point? Why

 

1.5m CH3CH2OH, 0.7m AlCl3, 1.2m C8NO3, 1m NaCl

1.5m CH3CH2OH becaues it doesn’t dissovle and thus has the lowest [ ] of dissolved species

Which of the following has the highest freezing point?Why?

 

1.5 m CH3CH2OH, 0.7m AlCl3, 1.2m C8NO3, 1m NaCL

0.7 m AlCl3 because it has the highest [ ] of dissolved species
What would be the freezing point of a solution prepared by dissolving 117g of NaCl in 1kg H2O (KF,water=1.86°C/m)? Why?
-7.44 because of the vant Hoff factor of 2 thus it would NOT be -3.72

Which of the following is a valid rate expression for the following reaction:
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g)

 

[image]    [image]  [image]   [image]

[image] because valid rate expressions are positive for products and negative for reactants.


Thus, choice 1 would be correct if if were 1/5 instead of 5/1

If a second order reactant is increased by a factor of 10 how much is the rate of reaction increased by?
100
If the [ ] of 1st order is doubled and the [ ] of the second order is tripled, what is the overall net rate of reaction?

2*1=2 3^2=9

 

9*2=18

 

18

What are the only things that can affect K?
temperature change and catalyst

In the following equation, what will maximize CO production?

 

2C(s) + O2(g) —> 2CO(g)    delta H = -566kJ

 

Decrease the volume, decrease temperature, remove O2, increase pressure

Decrease the temperature. Since it is an exothermic reaction, heat is assumed to be a product and if you lower the temperature it will shift the reaction to the right
What is the molar solubility of AB3, Ksp = 3.0*10^-19 ?

3x^3*x = 27x^4=3.0*10^-19

 

3.0*10^-19/27=x^4

1.0*10^-20=x^4

 

x=1.0*10^-5

What is the Ksp if the molar solubility of

MX2 is 2.0*10^-6 M?

 

4x^3=Ksp

4(2.0*10^-6)^3=Ksp

 

4*8.0*10^-18 = Ksp

 

Ksp = 3.2*10^-17

What is the molar solubility of BaF2 in 0.1M NaF

Ksp, BaF2 = 3.2*10^-8

 

 

3.2*10^-8 = x * 0.1^2

 

3.2*10^-8/0.1^2 = x

 

x = 3.2*10^-6 M

If Ksp > Qsp, which way does the reaction shift? What is the result (precipitate or not)?
Shift right. No ppt occurs

Which of the following will AgCl be least soluble? Why?

 

.15M AgNO3, .08M MgCl2, Pure H2O, 0.1M HCl

.08M MgCl2 because it has the highest [ ] of common ion with AgCl.

What is the strongest acid listed here? How do you know?

 

H2O, H2S, H2Te, H2Se

H2Te because it is furthest down the periodic table
How much more acidic is pH 1.5 than pH 4.0?
10^2.5 = 300 or so
Strong Acid: If [H+] = 2.0*10^-4 M what is the pH? If this were a weak acid, what would be needed to solve this problem?

-log(2.0*10^-4) = 3.8

 

If this were for a weak acid, Ka would be needed to solve this problem

What is the pH of 0.1M HCN (Ka = 5.0*10^-10)?

 

Ka=([H+][A-])/[HA]

 

5.0*10^-10*0.1=x^2

5.0*10^-11=x^2

-log(5.0*10^-5.5)=x

 

x=5.2

Which of the following has a pH closest to 7 and why?

 

KClO2, CaCl2, Al(NO3)3, NaHCO3

CaCl2 because both Ca and Cl are negligible ions meaning that it is a neutral salt.

Which of the following would form a buffer solution and why?

.1M HBr and .1M KBr

.1M HClO4 and .1M KOH

.1M HClO2 and .1M NaClO2

.1M HF and .1M NaOH

.1M HClO2 and .1M NaClO2 because this is the only choice that contains a weak acid (HClO2) and its conjugate base (NaClO2)

What is the pH of a solution with .05M HF and .05M NaF

Ka, HF = 6.8*10^-4

 

.05/.05 = 1 so pH = pKa

-log6.8*10^-4 = pKa

 

pKa=pH=3.2

What is the pH of a solution containing .003M HF and .02M NaF?

Ka, HF = 6.8*10^-4

pH = pKa + log[A-]/[HA]

pKa=-logKa=3.2

.02/.003 = 6.67*10^1

log6.67*10^1=.8

 

3.2+.8 = 4.0

How much heat is released when 120 grams of Ca(s) reacts with O2

Delta H not = -1271 kJ

 

2Ca(s) + O2 (g) —> 2CaO(s)

120g*(1/40g)*(1271/2mol Ca) = 1.5

 

1271*1.5 = 1907 kJ

When is entropy change observed at a value of close to zero?
When the moles of gas in the products and reactants are the same

Which of the following is a formation reaction? Why?

 

C + O2 (g) —-> CO2(g)

N2(g) + H2(g) —> 2NH3(g)

C+CO2(g) —>2CO(g)

1/2 H2(g) + 1/2 N2(g) + 3/2 O2(g) —>HNO3(g)

1/2 H2(g) + 1/2 N2 (g) + 3/2 O2(g) —> HNO3(g)

 

because all of the reactants are in their standard state and there is only one mole of product

Which of the following is false about an electrolytic cell and why?

 

E is consumed, e- from anode to cathode, oxidation @ cathode, electricity is used

oxidation occurs at cathode because the cathode has a negative charge so the more positive species will be attracted to the cathode. Thus, it will gain electrons fitting the definition of being reduced
What are the products of molten electrolysis of NaCl?
Na and Cl2
What is the 1/2 reaction at the CATHODE for the molten electrolysis of CdCl2?
Cd2+ + 2e- —> Cd

How many moles of e- are produce by the electrolysis of NiCl2 using 10 Amps for 30 min. F=96500

 

(Not exact number just the intermediate step to solve for the answer)

10 * 1800/(2*96500) = # moles
Metals are said to be malleable and ductile. What do each of these mean, respectively?

Malleable- deformed w/o breaking

ductile- drawn into wires

What is Dalton’s Law?
Total pressure is the sum of all the partial pressures
x

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