The Gas Phase

Question 1

Four Gas Variables

Answer 1

• Pressure (P)
• Temperature (T)
• Volume (V)
• Number of moles (n)

Question 2

Unit(s) of Pressure

Answer 2

Pressure = atm, mmHg, torr, kPa

Note:
[1 atm = 760 mmHg = 760 torr = 101.325 kPa]

Question 3

Unit(s) of Temperature

Answer 3

Temperature = K

Note:
273 + C = K
K - 273 = C

Question 4

Unit(s) of Volume

Answer 4

Volume = L or mL

Note:
1 L = 1000 mL or 1 x 10^3

Question 5

Standard Temperature and Pressure

Answer 5

STP = 273 K (0 C) @ 1 atm

Used for Gas Law Equations

Note:
@ STP 1 mole of ideal gas = 22.4 L

Question 6

Ideal Gas

Answer 6

A hypothetical gas where molecules do not exert intermolecular forces and do not occupy any volume.

Question 7

Ideal Gas Law

Answer 7

Def.) Describes relationship between P, T, V, and n.

Eq.) PV = nRT

R = 8.314 when P = kPa
R = 8.21E^-2 when P = atm
R = 62.4 when P = mmHg

Question 8

Ideal Gas Law: Solve for Pressure (P)

Answer 8

P = nRT/V

Question 9

Ideal Gas Law: Solve for Volume (V)

Answer 9

V = nRT/P

Question 10

Ideal Gas Law: Solve for Number of Molecules (n)

Answer 10

n = PV/RT

Question 11

Ideal Gas Law: Solve for Temperature (T)

Answer 11

T = PV/nR

Question 12

Ideal Gas Law: Density

Answer 12

d = PM/RT

Note:
d = density
M = molecular weight

Question 13

Combined Gas Law

Answer 13

[P1V1/T1] = [P2V2/T2]

Question 14

Avogadro’s Principle

Answer 14

P and T held constant; shows n and V are directly proportional

n/V = k n1/V1 = n2/V2

Note:

• increase in n = increase in V
• decrease in n = decrease in V

Question 15

Boyle’s Law

Answer 15

T and n held constant; shows P and V are inversely proportional

PV = k P1V1 = P2V2

Note:

• increase in P = decrease in V
• decrease in P = increase in V

Question 16

Gay-Lussac’s Law

Answer 16

V and n held constant; shows T and P are directly proportional

P/T = k P1/T1 = P2/T2

Note:

• increase in P = increase in T
• decrease in P = decrease in T

Question 17

Charles Law

Answer 17

P and n held constant; shows T and V are directly proportional.

V/T = k V1/T1 = V2/T2

Note:

• increase in V = increase in T
• decrease in V = decrease in T

Question 18

Gas Properties

Answer 18

• Least dense
• Indefinite volume or shape
• Easily compressible
• Homogenous mixtures
• Same temperature = same kinetic energy
• Exist at high temperatures and low pressures