Chap 13

Question 1

kinetic molecular theory (KMT) of gases

Answer 1

1. all gases are composed of tiny particles called molecules. the molecules are very far apart, and the volume of the molecules is extremely small compared to the total volume of gas. a gas is mostly empty space.
2. gas molecules are in constant, rapid linear motion. the pressure of a gas is a result of the collision (force) of the molecules with the walls of the container (surface area). P = F / A.
3. the collisions between molecules are completely elastic (no kinetic energy is lost). the pressure of a gas in a container remains the same as long as temperature remains constant.
4. the molecules of a gas do not attract or repel one another.
5. at any moment the molecules have different velocities. the average kinetic energy (KE = 1/2 mv^2) of the molecules is directly proportional (mass velocity) to absolute (Kelvin) temperature.

Question 2

Boyle’s Law

Answer 2

volume and pressure are inversely proportional if temperature and amount of gas remain constant.

V is proportional to 1/P VP = constant
V P = V P

Question 3

pressure / temperature law

Answer 3

pressure and absolute temperature are directly proportional at constant volume and amount of gas

P is proportional to T P/T = constant P / T = P / T

Question 4

Charles’ Law

Answer 4

volume and absolute temperature (Kelvin) are directly proportional if pressure and amount of gas are constant.

V is proportional to T V/T = constant V / T = V / T

Question 5

conversions

Answer 5

760 mm Hg = 1 atm

1 atm = 101.3 kPa

Question 6

Dalton’s Law

Answer 6

the total pressure or a mixture of gases is equal to the sum of the partial pressures of the individual gases

P = P + P + P …….

Dalton’s Law is used when a gas is collected by bubbling and through water.

P = P + P P = vapor pressure of water

Question 7

Graham’s Law

Answer 7

the rate of diffusion or effusion of a gas is inversely proportional to the square root of its density or square root of its molecular mass.

(lighter gases diffuse faster than heavier gases)

Rate is proportional to 1/ MM 1 / d

For comparing the rates of diffusion of two gases: Rate / Rate = MM / MM

Question 8

Ideal Gas Law

Answer 8

PV = nRT

P = pressure, V = volume, n = moles of gas

R = ideal gas constant
= .08206 L atm/mol K

T = temperature in kelvin