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Question 1

calorie to joules

Answer 1

4.2

Calorie is 4.2 J

Calorie > Joule

1 kCal = 4.2 (10)^3 joules

Question 2

standard conditions versus STP (IMPORTANT)

Answer 2

1 ATM, 298 K

STP (standard temperature and pressure) is 273 K!

Question 3

heat of formation (∆H*_f )

Answer 3

O2, H2, Cl2 are naturally diatomic

O2 = 0
O = 249 kJ/mol (energy needed to break the bond)

Question 4

homolytic cleavage (Bond Dissociation Energy)

Answer 4

the stronger the bonds of the formed product (less enthalpy), the more exothermic

STRONGER BONDS = REDUCED ENTHALPY = EXOTHERMIC

Question 5

heat of reaction

Answer 5

Bonds broken - Bonds formed

Question 6

heat of fusion

Answer 6

solid to liquid

“fusing solid into liquid”

heat is RELEASED when steam CONDENSES into liquid

Question 7

rules for entropy (IMPORTANT)

Answer 7

1. Gases > liquids > solids (CHECK THIS! this is important!)
2. particles in solution > solids
3. 2 moles > 1 mole

Question 8

Ice -> Liquid -> Gas

Answer 8

ENDOTHERMIC, gas has higher enthalpy than ice

gas condenses to liquid, crystalizes to solid (EXOTHERMIC)

Question 9

sublimation/deposition

Answer 9

deposition: Heat released, Internal KE decreases, entropy decreases

Question 10

fusion

Answer 10

SOLID to LIQUID (“fusive liquid”)

Question 11

phase diagram for water

Answer 11

solid-liquid line is NEGATIVE slope due to denser liquid phase than solid

Question 12

gas to liquid to solid (remember thing significant changes)

Answer 12

HEAT is RELEASED
Internal KE decreases
Entropy DECREASES

Question 13

Ideal gas assumptions

Answer 13

1. molecules are small = no volume
2. collisions mean pressure
3. no intermolecular forces
4. KE of molecules is proportional to Temp

Question 14

1 atm = 101.3 kPa

Answer 14

760 mm Hg or 760 torr

1 atm approximately 1 barr

Question 15

PV = nRT (what is R) (IMPORTANT!)

Answer 15

0.0821

Question 16

Charles’s law

Answer 16

temperature increases volume

Pressure = CONSTANT

Question 17

Boyle’s law

Answer 17

PV is constant

“Boyle PV”

Constant Temperature

Question 18

Gay-Lussac

Answer 18

Temperature and pressure in constant volume

Question 19

Equal-volume containers, same temperature and pressure

Answer 19

SAME n MOLES of compound

Question 20

At 0˚C and 1 atm, 1 mole of gas occupies…

Answer 20

22.4 L

Question 21

deviations from ideal gas law

Answer 21

P_real < P_ideal (intermolecular forces)

volume_real < V_ideal (the particles take up empty space)

more ideal if the particle is SMALL

higher temperature = MORE IDEAL (low temperature causes condensation, which is more like liquid)

LOWER PRESSURE = MORE IDEAL (high pressure causes intermolecular mores, limits volume of actual empty space)

Question 22

Polyatomic OCCUPY MORE VOLUME than monoatomic, even CH4 (16) and Ar (40 amu)

Answer 22

x

Question 23

Partial pressure is related to MOLE FRACTION

Answer 23

if total pressure is 8 atm and Particle_A is 1/2 total moles, then Particle_a has 4 atm partial pressure

Question 24

rms

Answer 24

KE is proportional to Temperature for ALL molecules in a gas

1/2mv^2 = 1/2mv^2

smaller mass, faster particle

RMS is the (larger/smaller)^1/2

(Memorize: Graham’s law of effusion p. 754)

Question 25

Q: SOLIDS are least entropic

Answer 25

Solids are not necessarily polar/ionic