CH 301 Final Exam

Number of Protons =

Atomic Number (bottom)

Number of Neutrons =

Mass Number - Atomic Number

Number of Electrons

Atomic Number - Charge

1

Mono

2

Di

3

Tri

4

Tetra

5

Penta

6

Hexa

7

Hepta

8

Octa

9

Nana

10

Deca

Molecular Compounds =

Nonmetal + Nonmetal

Molecular Compounds

Use Prefixes

Ionic Compounds =

Metal + Nonmetal

Ionic Compounds

Do NOT use prefixes

Ammonium

Bicarbonate

Carbonate

CN - 3

Cyanide

Hydroxide

Nitrate

CN - 3

Nitrite

Peroxide

Phosphate

SP - 4

Sulfate

SP - 4

Sulfite

Equation for calculating the percent composition of an element

Ammonia

Diatomic Elements

Br I N Cl H O F

1 KJ

1000 J

1 L

1000 mL

What do you use to convert grams of a substance to moles of that substance?

Molar Mass (#g/1mol)

4 Steps for Gram to Gram Conversion

Grams x Molar Mass x Molar Ratio x Molar Mass = Grams

Solute

Thing being dissolved

Molarity (M) =

Moles of Solute/Liters of Solution

Mass =

Moles x Molar Mass

Equation for 2 values of Molarity and 2 values of Volume

M1V1 = M2V2

Sodium Dichromate

Na2Cr2O7

How do you find the oxidation state of an element in a compound?

1) write an equation based on the compound, 2) set the equation equal to the net charge, 3) solve for the unknown value

No net charge in a compound =

zero

What has an oxidation state of zero?

Any element in its pure elemental form (Ex. H2, N2, O2)

Oxidation state of Fluorine

-1

Oxidation state of Oxygen (Oxide)

-2

Oxidation state of Oxygen (peroxide)

-1

Oxidation state of Hydrogen (Bonded to a Nonmetal)

+1

Oxidation of Hydrogen (Bonded to a Metal)

-1

Calcium Hydride

CaH2

Hydrogen Peroxide

H202

Sulfuric Acid

H2SO4

In a M1V1 = M2V2 problem with 2 different solutions (2 different substances)….

take into account the molar ratio found in the balanced reaction of the 2 substances

“Concentration” =

Molarity (M)

What two ions always produce H2O when paired up?

H+ & OH-

Step 1 of writing a balanced reaction:

Write the reactants like R + R —> ?

Step 2 of writing a balanced reaction:

Write down the oxidation states (charges) of each reactant

Step 3 of writing a balanced reaction:

Pair the two inside terms and the two outside terms of the reactants

Step 4 of writing a balanced reaction

Use the criss-cross method to determine the products

Step 5 of writing a balanced reaction

Add the products to the equation

Step 6 of writing a balanced reaction

Balance the reaction

SATP =

T = 298 k & P = 1 atm

STP =

T = 273 k, P = 1 atm, & 1 mole of any gas = 22.4 L

Combined Gas Law

Volume units when using the combined gas law

mL OR L

Pressure units when using the combined gas law

atm OR torr

Temperature units when using the combined gas law

k ONLY

Density =

Mass/Volume

To find the density of a gas at STP…

take the molar mass (g/mol) and multiply it by 1mol/22.4 L

Density also =

(Pressure x Mass)/R x Temperature; R = 0.08206 (L x atm)/mol x k

If pressure is in atm use

0.08206 (L x atm)/mol x k for R

Ideal Gas Law

PV = nRT

When you’re trying to find the identity of an unknown gas…

find the molar mass of each answer choice and compare it with the molar mass of the unknown gas

When you have a “collected over water” problem…

you must consider the partial pressure of water (Ptot = Pgas + PH20)

Units of Molar Mass

#g/1 mol

1 atm =

760 torr

Vapor pressure of water =

partial pressure of water

The average kinetic energy of a sample of gas is dependent on

temperature

For a sample of gas KE =

3/2RT

Temperature and the average kinetic energy of a sample of gas are

Proportional

The average velocity of gas particles is dependent on

temperature

The root mean square velocity of a gas =

M = molar mass (kg/mol); R = 8.314 J/mol x k

Vrms and Temperature are

proportional (gas particles move faster at a higher temperature)

Pressure =

Force/Area

Heavier gas particles move

slower

If you increase your mass, but decrease your speed, the pressure will

be the same

Force x contact time =

mass x delta velocity

Heavier gas particles

do NOT exert greater pressure

What’s an example of a very light gas?

Hydrogen Gas (H2)

What’s an example of a very heavy gas?

Chlorine Gas (Cl2)

According to the ideal gas law, the pressure must be the same, regardless of whether one gas is light or one is heavy if

the volume, moles, and temperature are the same

The pressure inside a container is dependent on

the total number of moles of gas particles inside the container (bc n is part of the ideal gas law; n inc = P inc)

Under what conditions will a real gas behave like an ideal gas?

High temperature, Low pressure

What kind of pressure favors the formation of liquid

High

The specific heat capacity of water (l) is

4.184 J/g x degrees Celsius

Equation for heat energy (q) with a temperature change =

Equation for heat energy (q) with a phase change and units kJ/mol =

q = n x delta H

Equation for heat energy (q) with a phase change and units J/g =

q = m x delta Hfus

Fusion (s —> l) is an

endothermic process so q = +; delt H = +

Freezing (l —> s) is an

exothermic process so q = -; delta H = -

Phase change from gas to solid

deposition (exo)