Chemistry Chapter 7-8

Question 1

Combination

Answer 1

A+B = AB

Question 2

Decomposition

Answer 2

AB = A+B

Question 3

Single Replacement

Answer 3

A+BC = AC+B

Question 4

Double Replacement

Answer 4

AB+CD = AD+CB

Question 5

Combustion

Answer 5

Cx + Hy + O2 = CO2 + H2O

Question 6

Steps of Combustion

Answer 6

Step 1: Put 2 in front of CxHy and distribute
Step 2: Go to H and H2O, balance and distribute
Step 3: Balance C in CO2 and distribute
Step 4: Add up Os on the right and the balance on the left
Step 5: Reduce if everything is reducable
Add Ratio and Balanced

Question 7

OIL RIG

Answer 7

Oxidation is loss of electrons
Reduction is gain of electrons

Question 8

Rules of Oxidation Reduction

Answer 8

1: Assign free elements a charge of 0
Ex: Cu or Fe2
Diatomic elements are free elements
2: Assign other charges based on oxidation numbers charges
ex: 2Cu^0 + O2^0 = 2Cu^+2O-2
3: Compare the charges and identify as oxidation or reduction

Question 9

Oxidation reaction is when

Answer 9

0 goes to positive charge
Loses electrons
ex: 0 to 2+

Question 10

Reduction reaction is when

Answer 10

0 goes to negative charge
Gains electrons
ex: 0 to 2-

Question 11

If there is an e- on the left it is

Answer 11

reduction

Question 12

If there is an e- on the right it is

Answer 12

oxidation

Question 13

Oxidation always

Answer 13

loses electrons, may also be seen as an addition of oxygen or loss of hydrogen

Question 14

Reduction always

Answer 14

gains electrons, may also be seen as loss of oxygen or gain of hydrogen

Question 15

Half Redox reaction

Answer 15

Cu^0 + 2AgNO3 = Cu(NO3)2 + 2Ag
Cu goes from 0 to 2+
Ag goes from 1+ to 0

Half Redox:
Cu^0 = Cu^+2 + 2e-
Oxidation

Ag^+1 + e- = Ag^0
Reduction

Question 16

What is a mole?

Answer 16

Unit of measurement, amount of a pure substance containing the same number of chemical units (atoms or molecules)

Question 17

Avagadro’s Number

Answer 17

6.02 x 10^23 particles

1 mole / 6.02 x 10^23 or 6.02 x 10^23 / 1 mole

Question 18

Moles of an element in a compound

Answer 18

Subscripts are used to write conversion factors for moles of an element

Question 19

How many atoms of O are in 0.150 mole of C9H8O4?

Answer 19

3.61 x 10^23 atoms of O

Question 20

How many CO2 molecules are in 0.500 mole of CO2?

Answer 20

3.01 x 10^23 molecules of CO2

Question 21

What is the number of moles in 1.8 x 10^24 atoms of S?

Answer 21

3.0 moles of S

Question 22

Molar Mass

Answer 22

quantity in grams that equals atomic mass
ex: Na molar mass = 23g
H2 molar mass = 2g

Question 23

Molar mass of compounds

Answer 23

Add all element’s molar mass together
ex: C2H6O
C = 2 x 12.01
H = 6 x 1.01
O = 1 x 16.0
= 46.0 g/mol

Question 24

Calculations using molar mass

Answer 24

A box of salt contains 737g of NaCl, how many moles of NaCl are in the box?
12.6 moles of NaCl

Question 25

Law of conservation of mass

Answer 25

Matter cannot be created or destroyed No change in total mass occurs Mass of products is equal to mass of reactants

Question 26

Mole-Mole Factors, how many moles of each reactant and product are in 2Fe + 3S = Fe^2S^3

Answer 26

2 moles Fe, 3 moles S, 1 mole Fe2S3

Question 27

What is the mole mole factor for 3H2 + N2 = 2NH3

Answer 27

1 mole N2 / 3 mole H2 or 3 mole H2 / 1 mole N2

Question 28

Calculations using mole factors

Answer 28

4Fe + 3O2 = 2Fe2O3 How many moles of Fe2O3 can form from 6.0 moles of O3? 4.0 mole of Fe2O3

Question 29

How many mole of Fe are needed for the reaction of 12.0 mole of O2? 4Fe + 3O2 = 2Fe2O3

Answer 29

16.0 mole of Fe

Question 30

Converting mass calculations (g to mole to g)

Answer 30

Multiply the top first, then the divide by the bottom 4Na + O2 = 2Na2O How many grams of Na2O are produced when 57.5 grams of Na react? 77.5 g NaO2

Question 31

Limiting Reactant (LR)

Answer 31

Substance that is used up first Limits the amount of product that can form Reactant that runs out first

Question 32

Excess reactant

Answer 32

What doesn't run out/what is left over

Question 33

Calculating LR

Answer 33

Ex: You have 3 mole of CO and 5 mole of H2, how many mole of CH4O? CO + 2H2 = CH4O H2 is the LR

Question 34

What is the LR in this equation

Answer 34

N2 + 3H2 = 2NH3 You have 2.50 g N2 and 2.00 g H2, what is the LR of 2NH3? N2 is the LR

Question 35

Exothermic

Answer 35

Heat is released, negative # ex: H2 + Cl2 = 2HCl + 185 kj Heat = -185

Question 36

Endothermic

Answer 36

Heat is absorbed, positive # ex: N2 + O2 + 180 kj = 2NO Heat = 180 kj

Question 37

Heat of reaction is

Answer 37

-the amount absorbed or released during a reaction that takes place at constant pressure -Change occurs when reactants interact, bonds break apart or when products form

Question 38

Heat of reaction formula

Answer 38

Heat = H (products) - H (reactants)

Question 39

How much heat in Kj is released when nitrogen and hydrogen react to form 50.0 g of ammonia? Heat = -92.2 Kj

Answer 39

N2 + 3H2 = 2NH3 - 135 Kj Exothermic

Question 40

Combined Gas Law formula

Answer 40

P1V1/T1 = P2V2/T2

Question 41

Boyle's Law

Answer 41

T and n are constant P1V1 = P2V2

Question 42

Charle's Law

Answer 42

P and n are constant V1/T1 = V2/T2

Question 43

Gay - Lussac's Law

Answer 43

V and n are constant P1/T1 = P2/T2

Question 44

In combined gas laws, what is always constant?

Answer 44

n = moles Temp always needs to be in Kelvin

Question 45

Dalton's law of partial pressure

Answer 45

P total = P1 + P2 Rearrange to solve for unknown

Question 46

Ideal Gas Law

Answer 46

Pv = nRT P = pressure v = volume n = moles R = gas law constant T = temp

Question 47

How many L in 1 mole?

Answer 47

1 mole = 22.4 L

Question 48

Standard pressure

Answer 48

1 atm

Question 49

How many mmHg is in 1 atm

Answer 49

760 mmHg

Question 50

How many kpa is in 1 atm

Answer 50

101.3 kpa

Question 51

Absolute zero =

Answer 51

0 Kelvin or -273 C