Chapter 7 (Gases)

Question 1

Boyle’s law

Answer 1

Volume is inversely related to pressure. (P1V1 = P2V2)
So as you increase the pressure you decrease the volume. This is at a constant temperature.

Question 2

Charles’s law

Answer 2

Temperature and volume are proportional. (V1/T1 = V2/T2)
As you increase the temperature, you also increase the volume. This is at a constant pressure.

Question 3

Ideal gas law

Answer 3

PV = nRT
P = pressure (atm)
V = volume (L)
n = number of moles
R = constant (0.08206 (L*atm)/(mol *K))
T = temperature (K)

Question 4

Dalton’s law of partial pressures

Answer 4

The total pressure (P total) is equal to the sum of the partial pressures of all the gases in a mixture.
P total = P1 + P2 + …

Question 5

Define standard temperature and pressure (STP).

Answer 5

Temperature = 273.15 K (0 C)
Pressure = 1 atm

Question 6

Are gases low or high density? Why?

Answer 6

Low density; the molecules in a gas like to be far apart from each other and fill up the entire size of their container.

Question 7

What are the seven diatomic elements?

Answer 7

H2, N2, F2, O2, I2, Cl2, Br2
(Have No Fear Of Ice Cold Beer)

Question 8

What are the units of pressure?

Answer 8

Pressure is expressed as an amount of Force per Area:
P = F/A

Question 9

What are units of pressure?

Answer 9

Pascal (Pa), atmosphere (atm), bar, torr, mmHg

Question 10

What are the units of density?

Answer 10

Mass/Volume (m/V)

Question 11

What is absolute 0 Kelvin?

Answer 11

Where volume = 0

Question 12

Define standard molar volume.

Answer 12

It is the volume of 1 mole of an ideal gas at STP, which is 22.41 L

Question 13

How many torr is in 1 atm?

Answer 13

760 torr

Question 14

How many mmHg is in 1 atm?

Answer 14

760 mmHg

Question 15

What is the mole fraction (X)?

Answer 15

mole fraction is a ratio of the amount of moles from one substance in a mixture, divided by the total number of moles.

Question 16

What is the kinetic molecular theory of gases?

Answer 16

This describes the behavior of ideal gases.

Question 17

What is Boltzmann distribution?

Answer 17

This states that not all gases move at the same speed or have the same kinetic energy. The distribution describes the different speeds and energies of different gases.

Question 18

Define diffusion

Answer 18

This is the gradual mixing of two gases until the mixture is uniform.

Question 19

Define effusion

Answer 19

This is a gas escaping from a tiny seep.

Question 20

Graham’s law

Answer 20

The rate of effusion is inversely proportional to the square root of its molar mass.