Chapter 5 - Gases

Question 1

Diffusion

Answer 1

Process where gas molecules spread out in response to a concentration gradient.

Question 2

Effusion

Answer 2

• Process where gas escapes from a container into a vacuum through a small hole.
• Rate of Diffusion is inversely proportional to the square root of the molar mass.

Question 3

Torr

Answer 3

1 torr = 1 mmHg

Question 4

Atmosphere

Answer 4

1 atm = 760 mmHg

Question 5

Pascal

Answer 5

1 Pa = 1 N/m²

Question 6

Boyle’s Law

Answer 6

Volume is inversely related to pressure.

V ∝ 1/P

P₁V₁ = P₂V₂

Question 7

Charles’ Law

Answer 7

Volume is directly proportional to temperature.

V ∝ T

V₁ / T₁ = V₂ / T₂

Question 8

Avogadro’s Law

Answer 8

Volume is directly proportional to moles of gas.

V ∝ n

V₁ / n₁ = V₂ / n₂

Question 9

Ideal Gas Law

Answer 9

PV = nRT

Question 10

Molar Volume

Answer 10

The volume occupied by one mole of a substance.

Question 11

Density (gas)

Answer 11

• d* = ρM / RT
• ρ* = molar density
• M* = Molar Mass

Question 12

Dalton’s Law of Partial Pressures

Answer 12

P_total = P_a + P_b + P_c +…..

Question 13

Mole Fraction (X_a)

Answer 13

X_a = n_a / n_total

Question 14

Partial Pressure of a Gas

Answer 14

P_a = X_aP_total

Question 15

Kinetic Molecular Theory

Answer 15

A model of an ideal gas as a collection of point particles in constant motion undergoing completely elastic collisions.

Question 16

Kinetic Molecular Theory Assumptions

Answer 16

1. The size of a particle is negligibly small.
2. The average kinetic energy of a particle is proportional to the temperature (K).
3. The collision of one particle with another (or with the walls of its container) is completely elastic.

Question 17

Kinetic Energy of a particle

Answer 17

KE = ½mv²

Question 18

Mean Square Velocity

Answer 18

Urms = √(3RT / M)

Question 19

Mean Free Path

Answer 19

The average distance that a molecule travels between collisions.

Question 20

Diffusion

Answer 20

The process by which gas molecules spread out in response to a concentration gradient.

Question 21

Effusion

Answer 21

The process by which a gas escapes from a container into a vacuum through a small hole.

Question 22

Graham’s Law of Effusion

Answer 22

rate_a / rate_b = √(M_B / M_A)