K-state, Dr. Yasmin Patell

What is an amu?

An amu is an atomic mass unit. That is a mass unit equal to exactly one-twelfth the mass of carbon 12-atom.

 

Therefore 1 atom of 12C "weighs" 12 amu.

The weights listed on the periodic table are all the __________ atomic mass.

average

Show the formula for finding the average atomic mass.

(Percentage1 x amu1) + (Percentage2 x amu2)

100

What is the numeral value for Avagadro’s number?
6.022 x 1023
What is a mol?
The mole(mol) is the amount of a substance that contains as many elementary entities as there are atoms in exactly 12.00 grams of 12C

What is the molar mass of anything?

It is the mass of 1 mole of a substance in grams.

For any element the atomic mass= the molar mass.

The sum of the atomic masses(in amu) in a mole is what?
The molar mass

This is the sum of the atomic masses(in amu) in a formula unit of an ionic compound.

The Formula mass

For any molecule

what = what?

the molecular mass (amu)=the molar mass (grams)

For any ionic compound

what always = what?

Formula mass (amu)= molar mass (grams)

what is this formula?

;

n x molar mass of element ; x;100%

molar mass of compound;;; ;;;;;;;;;

Percent composition
What is the percent composition?
It shows the different percentages that make-up a substance.
What is are the three steps of going from a mass percent, to an empirical formula?

1. convert the mass percent to grams and divide by the molar mass, which gives the moles of each element.

2. divide the moles of each element by the smallest number of moles, which gives the mole ratios of elements

3.change the mole ratios of an element to integer subscripts, and that produces the empirical formula.

Once you have the empirical formula you must (_______) the subscripts by an intergral factor to obtain the molecular formula.
multiply

;;Molecular mass of a compound;; = (WHAT?)

empirical molar mass;;;;;;;;;;;;;;;

the intergral factor

What is a chemical reaction?

Where one or more substances are changed into one or more mew substances.
What is a chemical equation?
It uses chemical symbols to show what happens during a chemical reaction.

2 NH3

;

;

What is the proper name for the 2 in this molecule?

Stoiciametric coefficiant

What is the best way to get the best way to get the amounts of reactants and products?

____-;____-;____-;____

grams-;mols-;mols-;grams
What is the limiting reactant?
It is the reactant that runs out, is used up, first.
What is the theoretical yeild?

It is the amount of product that would result if all the limiting reagent reacted.

What is actual yeild?
It is the amount of product actualy obtained from a reaction

Actual Yield;;;;;;;x 100

Theoretical Yield;;;;;;;;;;;;;;;

;

;

What formula is this?

The formula for % Yield
What is a solute?

It is a substance that is present in the smaller amounts of the solution

What is a homogenous mixture of two or more substances?
A Solution

What is a solvent?

It is the substace present in the larger amount in the solution.

_____ is a substance that, when dissolved in water, results in a solution that can conduct elecctricity.

An Electrolyte
A non-electrolyte is?
A substance that, when dissolved in water, results in a solution that does not conduct electricity.

What is 100% dissociated into ions? A strong or weak electrolyte?

A strong, it is an electrolyte that exists in a solution almost entirely as ions.
What is only partially dissociated into ions? A strong or weak electrolyte?
Weak electrolyte, it is an electrolyte that dissovles in water to give a relatively small percentage of ions. There is an equilibrium between the dissociated and non-dissociated species.

what does the following symbol mean?

;

——>

<—–

That the reaction is reversible, and that the reaction can occur both ways.

What type of electrolyte does NOT conduct electricity?

A non-electrolyte

Which of the following is a strong electrolyte?

 

HF

HCLO4

H2O

HCLO4
Is NaOH a strong electrolyte?
Yes

Which one of the following is a strong electrolyte?

 

NaCl

MgO

H2SO4

H2SO4

Choose the strong electrolyte(s)

 

Ba(OH)2

HCl

HNO3

Ionic Compounds

All of them
What are the two main categories for non-electrolytes?
sugars or alchohols
What happens in a precipitation reaction?

Two solutions on ionic compounds are mixed and a solid ionic substance(a precipitate) is formed.

This is an insoluable solid compound formed during a chemical reaction in solution.
A precipitate

Metathesis reaction is what?

is a reation in which the reacting species exchanges "partners".
To determine if an insoluable product will be formed, we must….?
Learn the soluablity rules.
What is soluability?
It is the maximum amount  of solute that will dissolve in a given quantity of solvent as a specific temperature.

What is a chemical equation in which the reactants and products are written as molecules or whole units?

Molecular Equation
An ionic equation is what?

It is a chemical equation in which the dissolved species are written as seperate ions in an aqueous solution.

This is an ionic equation from which the spectator ions have been cancelled out.
Net Ionic Equation

If A+B+ C+D- is the intial equation, what will the reaction be?

C+B + A+D
A Proton donor is a ______ acid
A Bronsted Acid
A Bronsted Base is what?
A proton acceptor.

A Bronsted Acid must contain at least one what?

ionizable proton

Which one, strong acids or weak acids, make strong electrolytes?

Strong Acids
Strong Acids and Strong Bases do what in water?
completely ionize

What is a Strong Base?

It is a base that ionizes completely in water.
This is a reaction between an acid and a base that results in an ionic compound(salt) and possibly water.

Neutralizatoin Reaction

Salt is an ionic compound whose cation comes from, where?

it comes from an acid

What does the net ionic equation for each acid-base reaction involve?
A transfer of protons
What do some certan salts (e.g. Carbonates, sulfites, and sulfides) react with acid to do what?
to form a gaseous product
What does OiLRiG stand for?
In an oxidation-reduction reaction, it is an easy way to remember which one does what. Oxidation Loses, it’s charge. While Reuction Gains a charge.
What is the name for the charge that the atom would have in a molecule (or an ionic compound) if electronswere completely transferred?

The Oxidation Number

What kind of charge do elements in their uncombinded states have?

they have an oxidation number of zero

What is the oxidation charge of monatomic ions?
The oxidation charge is equal to the charge on the ion.

What is usually the charge for Oxygen?

What about H2O2?

What about 022-

Usually the charge is -2

 

For peroxide it is -1

 

For Oxide it is -1

The sum of the oxidation numbers of all the atoms in a molecule or ion is equal to what?
It is equal to the charge on the molecule or ion.

What do Group IA metals have as their oxidation charge?

 

+1

Group IIA metals are what oxidation charge?

 

What charge is always Flourine?

+2

 

-1

What is the idea of a combination reaction?

A + B —> C

 

It is a reaction in which two or more substances combine to form a single product

This is a reaction in which a single compound reacts to give two or more substances.

A Decomposition Reaction

 

C —> A + B

A displacement reaction is refered to as a…..?
Single-replacement
A Single-replacement action is an reaction in which what happens?
It is where one metal displaces another metal, or hydrogen, from a compound or aqueous solution.
A combustion reaction is what?
It is a reaction in which a substance reacts with oxygen, usually with the rapid release of heat to produce a flame.

What is a Disproportionate Reaction?

It is a reaction in which an element in one oxidation state is simultaneously oxidised and reduced.

The concentration of a solution is the amount of solute present in a given quantity of solvent or solution is what?

That is it’s Molar Concentration(molarity)
what is the formula for finding out the molarity of a substance?

Molarity =     moles of solute

                  liters of solution

what is this formula solving for?

 

Moles of solute

liters of solution

the molarity of a substance

 

it’s answer is going to be in:  mol/L

What is this equation for?

 

MiVi = MfVf

Dilution of a solution
Dilution is what?
It is the procedure for preparing a less concentrated solution from a more concentrated solution.
What is it when a solution of accurately known concentration is added gradually to another solution of unknown concentration until the reaction between the two solutions is complete?
Titration
This is the point at when an Acid-Base reaction is complete.

Equilalence point

The indicator in an Acid-Base reaction does what?
It is a substance that changes color at (or near) the equivalence point, indicating the end of the reaction.

 A gas is a substance that exists @ what temperature?

@ 25o C and 1 atm

What does a gas do to the volume of it’s container?

It assumes the volume and shape of it.
Is gas the most compressible state of matter?
Yes it is

Gases will not mix evenly and completely when confined to the same container?

 

 

True or False?

False

 

Gases will mix evenly and completely when confined to the same container.

Do gases have a much lower density than liquids or solids?

Yes they do.
What is the formula for pressure?

P=   Force

       Area

 

Force= mass x acceleration

1 N/m2 = what unit of pressure?

1 pascal(Pa)

760 torr = 760 mmHg = ???
1 atm
What is used to measure the atmosperic pressure?
A Barometer
Does atmospheric presure increase or decrease with altitude?
decreases, there is less atmosphere, therefore less pressure
mmHg is what?
manometers of Mercury
What is the equation for finding the pressure of a vaccum?
Pgas=Ph
What is the equation for an opened tube, used to measure pressure?
Pgas=Ph+Patm

The pressure of a fixed amount of gas maintained at constant temperature is inversely proportional to the volume of the gas.

 

What is this?

Boyle’s Law
In Boyle’s Law are Pressure and Volume proportional?
Yes: as the pressure goes up the volume will go down, and vica versa
State Boyle’s Law is Symbolic Terms
P1V1 = P2V2

The volume of a fixed amount of gas maintained at constant pressure is directly proportional to the absolute temperature of the gas.

 

What law is this?

What unit is the highlighted section in?

Charles’ Law

 

Kelvin:  (Co + 273)

In Charles’ Law, Volume is directly propotional to ?
Temperature
State Charles’ Law in symbolic form.

V1 = V2

T1    T2

In the event that all three parameters, Pressure, Volume, and Temperature, are changing, what Law would you use? Boyle’s or Charles’?

BOTH!!! HAHA I TRICKED YOU!!!

 

you use the combined gas law

 

 

 

 wow…that was good!

State the combined gas law in symbols.

P1V1 = P2V2

T1        T2

At constant pressure and temperature, the volume of gas is directly proportional to the number of moles of gas present.

 

What law is this?

Avogadro’s Laws

 

(Tip for remembering: it uses the thing that Avogadro was famous for)

In Avogadro’s Law, is the volume and number of moles(n) directly proportional?
yes they are.
What is the formula for Avogadro’s Law?

V1 = V2

n1    n2

What is the formula for the ideal gas law?

PV = nRT
What is the definition of R in PV = nRT?
It is the gas constant.

What is the numerical value of R in PV = nRT?

R = .0821 L atm

               mol K

What is the name for the conditions 0oC and 1 atm?
They are the standard temperature and pressure (STP)

Density calculations are done by dividing PM by what?

d=  PM

       RT

 

Pressure x Molar Mass

       R(gas constant) x Temperature      

 

 D also = m/V

Show the formula for the Molar Mass of a Gaseous Substance.

 

What is the Symbol for Molar Mass?

M= dRT

     P

 

d is the density of the gas in g/L

 

M

What does Dalton’s Law of Partial Pressures state?

Dalton’s law of partial pressures states that the total pressure of a mixture of gases is the sum of the pressures that each gas would exert if it were present alone.

State Dalton’s Law in a formula.
Ptotal = P1 + P2

State what the symbols of the following formula mean.

 

PA = XAPT

PA = Partial Pressure of Gas

XA= mol fraction of Gas

PT = Total Pressure

 

XA = nA / nT

 

Could the first formula substitute for the second?

 

PA = XAPT

 

PA = ( nA / nT ) PT

Yes it will
x

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