Final Review

Honors Chemistry

Classes of matter

Physical Changes

- are those in which the identifying properties of a substance are unchanged

- Ex. : change of phase breaking, cutting

dissolving

Chemical Changes

- are those in which different substances are formed

- Ex.: burning rusting decaying or spoiling acid reacting with metal

subatomic particles

Atomic no.=# protons

#protons=#electrons

Mass no.=#protons +

# neutrons

Electron configuration notation

Helium has 2 electrons, so its electron

configuration would be 1s2

Li 1s22s1

N 1s22s22p3

Ne 1s22s22p6

Na 1s22s22p63s1 or [Ne]3s1

Principal quantum number

sublevel

No. of electrons

Every orbital can hold two electrons.

“d” orbitals

Predicting electron configurations from the

periodic table.

Ways to represent titanium

1s2 2s2 2p6 3s2 3p6 4s2 3d2 electron configuration

E E E E E E E E E E h h __ __ __

1s 2s 2p 3s 3p 4s 3d Ti: 22 2 8 10 2

How would calcium and chlorine combine?

Ca Cl Cl

CaCl2

Write the formulas- always put the cation first

K+ and N3-

K3N

Ca2+ and N3-

Ca3N2

Ba2+ and NO3-

Ba(NO3)2

Criss-cross rule of thumb

Naming molecular compounds

Use prefixes 1 mono-

2 di-3 tri-4 tetra-5 penta-6 hexa-7 hepta-8 octa-9 nona-10 deca-

My favorite “no”

nameNH4CO3

Write the formula forCalcium chloride

Nitrogen tetrahydrogen carbon trioxide

CaCl

Ionic or covalent?

NaBr CH4

Fe2O3

CO2

CaO NH4Cl SiCl4

Name

ionic

covalent

ionic

covalent

ionic

ionic

covalent

Sodium bromide

Carbon tetrahydride

Iron oxide

Carbon dioxide

Calcium oxide

Ammonium chloride

Silicon tetrachloride

Types of reactions

Decomposition: AB g A + BSynthesis (or “combination”): A + B g

ABSingle Replacement (or

“displacement”): A + BC g B + AC Double Replacement (or

“displacement”): AB + CD g AD + CBCombustion: CH4 + 2O2 g CO2 + 2H2O

Balance and classify Al + Cl2 AlCl3

2Al + 3Cl2 2AlCl3

Zn + HCl ZnCl2 + H2

Zn + 2HCl ZnCl2 + H2

Mg(ClO3)2 MgCl2 + O2

Mg(ClO3)2 MgCl2 + 3O2

C4H8 + O2 CO2 + H2O

C4H8 + 6O2 4CO2 + 4H2O

Writing Balanced equations

(NH4)2CO3 + Ba(NO3)2 g NH4+

CO32- Ba2+ NO3

-

NH4+

NO3-

+

2NH4NO3BaCO3i

Double displacement

Net ionic: CO32- + Ba2+ gBaCO3i

Chemical reactions involve energy

Endothermic reactions absorb energyex.: photosynthesis

CoCO3 + 81.6 kJ g CoO + CO2 Exothermic reactions give off energy

ex.: burning of woodC(s) + O2(g) g CO2(g) + 393.5 kJ

Reaction Tendencies

Reactions occur spontaneously when a lower energy state is achieved.In exothermic reactions, the products have less energy than the reactants.

Reactions occur spontaneously when a state of less order is achieved.Entropy is the disorder in a system.

Molecular mass (molar mass)

NaCl23.0 + 35.5 = 58.5

Ba(NO3)2

137.3 + 2(14.0) + 6(16.0) = 261.3

CuSO4∙5H2O

63.5 + 32.0 + 4(16.0) + 10(1.0) + 5(16.0) = 249.5

Solution concentrations

Percentage by weight. g solute x 100%

g solution g solute x

100% g solute + g solvent

Molality moles solute = m kg solvent Molarity M = moles solute L solution

M∙V = moles Dilutions TitrationsM1V1 = M2V2 MaVa = MbVb

If I wanted 100ml of 2.0M HCl, how much 6.0M HCl would I need?

6.0M x ?ml = 2.0M x 100ml 33.3ml

Conversion Factors

Molar mass atomic mass in g = 1 mole Volume of gas At STP, 1 mole gas = 22.4L

Mole-mole ratio coefficients from balanced equation

Avogadro’s number 6.02 x 1023 molecules = 1 mole

How many molecules are in 2.0 moles of H2O?

2.0 moles x 6.02x1023molecules

1 mole

What volume would 2.5 moles of H2 gas have at STP?

2.5 moles x 22.4L = 56L 1 mole

Stoichiometry

g g mole g mole

L(gas)

molecules

Molar mass

Molar mass

22.4L=1 mol6.02 x 1023 molecules = 1 mole

Multiple conversion factors may be needed

How many grams of CO2 are formed from 18.5 grams of O2 in the following reaction?

2C2H6 + 7O2 g 4CO2 + 6H2O

18.5 g O2 x 1mole O2 x 4 mole CO2 x 44 g CO2

32 g O2 7 mole O2 1mole CO214.5g

How many liters of CO2 are formed from 18.5 grams of O2 in the following reaction?

2C2H6(g) + 7O2(g) g 4CO2(g) + 6H2O(g)

18.5 g O2 x 1mole O2 x 4 mole CO2 x 22.4 liters

32 g O2 7 mole O2 1mole CO2

7.40L

Limiting Reactants In a chemical reaction, the reactant

which gets used up first limits how much product is formed.

i.e. If I had 5 moles of Al and 4 moles of Cl2, which reactant is limiting?

2Al + 3Cl2 g 2AlCl35 mole Al x 3 mole Cl2 = 7.5 mole Cl2 2 mole AlCl2 is limiting and Al is excess.

Have

Need

% yield = actual x 100% theoretical

If 5.50g of hydrogen reacts with nitrogen to form 20.4g of ammonia, what is the percent yield?

N2(g) + 3H2(g) g 2NH3(g)Actual = 20.4gTheoretical = 5.50g H2 x 1 mol H2 x 2mol NH3 x

17.0g NH3 2.0g H2 3mol H2 1mol

NH3

The amount of heat gained or lost depends on the amount of

reactants used.2Na2O2 + 2H2O g 4NaOH + O2 +

215.76 kJ

How much heat is released by the reaction of 5.0 moles of Na2O2?

5.0 moles Na2O2 x 215.76 kJ = 539.4 kJ 2 mole Na2O2

Q = m∙c∙∆T

Heat = mass ∙ specific heat∙ change

gained or lost in temp

Ex: How much heat is lost when a solid aluminum ingot with a mass of 411g cools from 660.0˚C to 25˚C? cAl =

0.903J/g˚C ∆T = 660.0 – 25 = 635˚CQ = (411g)(0.903J/g˚C)

(635˚C)=236,000 J

Charles Law V1 = V2 P constant

T1 T2

Boyles Law P1V1 = P2V2 T constant

Combined P1V1 = P2V2

T1 T2

Gay-Lussac’s Law P1 = P2 V constant

T1 T2

If temperature increases, volume ______.

increases. Always change Celsius to Kelvin

degrees.Ex.: If a gas expands from 125ml to

850ml, its original temperature of 15◦C must have changed to what?

15◦C=288K 288K x 850ml = 1958.4K 125ml

52.5 ml of a gas is collected over water at 20˚C and 100.0 kPa. What is the pressure of the dry gas?

100.0 kPa = Pgas + Pwater

Pwater at 20˚C = 2.3 kPa100.0 kPa – 2.3 kPa = 97.7 kPaWhat would be the volume of this gas

at STP? P1= 97.7 kPa P2=101.325kPaV1= 52.5 ml V2= ?T1= 20˚C=293 K T2=273 K

P1V1 = P2V2

T1 T2

52.5ml∙97.7 kPa = 101.325kPa ∙ V2

293K 273K

V2= 47.2ml

PV=nRT

P=Pressure V=volume n=moles R= gas constant = 0.0821 L∙atm mol∙K 8.31L·kPa mol∙K or 62.4 L∙torr mol∙K T= temperature (K)

When given three of the four variables, we can find the

fourth. A gas has a volume of 2.20L at 25◦C.

If there are .085 moles of the gas, under what pressure must the gas be held?

P = nRT V P = (.085mole)(0.0821 L∙atm)

(298K) 2.20L mol∙K

Compute the relative rate of diffusion of helium and argon.

16.3104

40

He

Ar

Ar

He

m

m

v

v

My favorite “no”

What volume of 2.0M HCl do you need to get .5 moles of HCl?

2.0M x 22.4L = 44.8L mole

[H+] = 10-pH [OH-] = 10-pOH

pH + pOH = 14.0

Sample problem:A 0.01 M sample of NaOH completely

ionizes. What is its pH, pOH, [H+], and [OH-] ?

[OH-] = 0.01 mole/L = 10-2 pOH = 2pH = 14 – pOH = 12 [H+] = 10-12

pH pOH [H3O+] [OH-]

6 8 10-6 10-8

1 13 10-1 10-13

Find the pH of a solution with [H3O+] of 6.59 x 10-10M.

pH = -log(6.59 x 10-10)pH = -(log 6.59 + log 10-10) = 9.18Find the [H3O+] of a solution with a pH

of 9.18.Antilog(-9.18)

Equilibrium Shifts

Concentration Removing products shifts equilibrium

right Adding a product shifts equilibrium

left

Pressure Increasing pressure on gases shifts

equilibrium toward side with fewer number of moles

Redox reactions

Identify the reducing and oxidizing agents.

Mg(s) + Cu(NO3)2(aq) Mg(NO3)2(aq) + Cu(s)

0 +2 +5 -2 +2 +5 -2 0

Mg is oxidized and is the reducing agentCu is reduced and is the oxidizing agent

Types of radiation

Alpha (α) low penetrating power

Beta (β) moderate penetrating power

Gamma (γ) high penetrating power

He42

e01

Transmutations

Complete the following nuclear equation.

KrRb 8336

8337 ?

e01

Half LifeIf you start with 2.97 x 1022 atoms of

,How many atoms will remain after 62

minutes? The half life of is 15.49 minutes.

62 = 4 half lives15.5

2.97 x 1022 atoms (½)4 = 1.86 x 1021 atoms

Mo9142

Mo9142

Fission- breaking apart of a nucleus

Can cause a chain reaction

Fusion- happens on the sun

TITRATION, NEUTRALIZATION…