Chapter 8- The Gas Phase

Question 1

Gas pressure units

Answer 1

1atm = 760mmHg = 760 torr = 101.325 kPa

Question 2

Ideal gas law

Answer 2

PV = nRT

Question 3

Solving for density

Answer 3

Density = m/V = PM/RT

Question 4

Number of L that 1mol of a gas at STP takes up

Answer 4

22.4L

Question 5

Combined gas law

Answer 5

PV/T = PV/T

Question 6

Calculate a change in volume

Answer 6

V2 = V1 (P1/P2)(T2/T1)

Question 7

Density

Answer 7

Density = mass/V

Question 8

Molar mass calculation

Answer 8

M = (density at STP) (22.4)

Question 9

Avogadros principle

Answer 9

n1/V1 = n2/V2

*as the number of moles of gas increases, the volume increases in direct proportion

Question 10

Boyles law (must be isothermal)

Answer 10

P1V1 = P2V2

*volume and pressure are inversely related

Question 11

Charles law (must have constant pressure)

Answer 11

V1/T1 = V2/T2

*volume and temperature are directly related

Question 12

Gay-lussacs law (constant volume)

Answer 12

P1/T1 = P2/T2

*pressure and volume are directly proportional

Question 13

Partial pressure calculation

Answer 13

(Moles gas A/total moles of gas) (total pressure)

Question 14

Vapor pressure

Answer 14

Pressure exerted by evaporated particles above the surface of a liquid

Question 15

What does increasing partial pressure of a gas do to the solubility?

Answer 15

Increases

Question 16

Evaporation and condensation equation

Answer 16

Vapor pressure from evaporated molecules forces some of the gas back into the liquid phase until equilibrium is reached b/w evap. and cond.

Question 17

Average molecular speed of gas particles

Answer 17

KE = (3/2)kBT

kB- 1.38 x 10^-23
T- temperature

Question 18

Almost impossible to find speed of individual gas molecule. What’s one way to determine an average speed?

Answer 18

Root-mean-square speed (Urms)

squareroot [3RT/M]
*higher temp =faster and larger molecules =slower

Question 19

Isothermal and isobaric conditions. Equation for rates at which two gases diffuse

Answer 19

r1/r2 = Squareroot [M2/M1]

Question 20

Diffusion

Answer 20

When gases mix with one another (high to low concentration)

Question 21

Effusion

Answer 21

When a gas moves the ought a small hole under pressure.

Question 22

Ideal gas law including density

Answer 22

T = (PM)/ (densityR)

Question 23

When to use what R-value?

Answer 23

.082 LatmmolK

8.314 JmolK