Chapter 1: 1.1 Gases

Question 1

Units

What is pressure measured in?

Answer 1

Pascal (Pa)

= Force per Area = N m^-2

Question 2

Define:

1 bar

Answer 2

10^5 Pa or 100 kPa

Question 2

Define:

1 atmosphere (atm)

Answer 2

101.325 kPa

Question 3

What are the three states of matter studied in chemistry?

Answer 3

Solids
Liquids
Gases

Question 4

What is a characteristic of a substance in a solid state?

Answer 4

Atoms, molecules, or ions are locked into a fixed position relative to others in the substance

Question 5

Give examples of:

Extremely strong and extremely weak forces that hold a solid lattice structure

Answer 5

• Extremely strong: Ionic solids
• Extremely weak: Inert gases

Question 6

Determine:

The relationship between interactions and the melting point of the solid

Answer 6

Stronger interaction = higher melting point

Question 7

What is required for gases to behave ideally?

Answer 7

1. Pressure is not too high
2. Temperature is not too low (close to condensation temperature)

Question 8

What is approximated in ideal gases?

Answer 8

1. Particles have no volume
2. Particles experience no attractive forces

Question 9

State:

Boyle’s Law

State constants

Answer 9

For a fixed amount of gas at a constant temperature, the gas volume is inversely proportional to the gas pressure

Amount of gas (n) and Temperature (T)

Question 10

State the formula and relationship for:

Boyle’s Law

Answer 10

P1V1 = P2V2
Pressure is inversely proportional to volume

Question 11

State:

Charles’ Law

State constants

Answer 11

The volume of a fixed amount of gas at constant pressure is directly proportional to the Kelvin (absolute temperature)

Amount of gas (n) and Pressure (P)

Question 12

State the formula and relationship for:

Charles’ Law

Answer 12

V1/T1 = V2/T2
Temperature is directly proportional to volume

Question 13

State the formula for:

The Combined Gas Law

State constants

Answer 13

(P1V1)/T1 = (P2V2)/T2

Amount of gas (n)

Question 14

State:

Avogadro’s Law

State constants

Answer 14

Equal volumes of different gases, at the same temperature and pressure, contain equal numbers of molecules

Temperature (T) and Pressure (P)

Question 15

State the formula and relationship for:

Avogadro’s Law

Answer 15

V1/n1 = V2/n2
Amount of gas is directly proportional to volume

Question 16

State the formula for:

Ideal Gas Law

State the constant

Answer 16

PV = nRT

R = Ideal Gas Constant

Question 17

State the Ideal Gas Constants (units)

Answer 17

• 0.08206 (L atm / mol K) [V in Litres, P in atmospheres]
• 0.08314 (L bar / mol K) [V in Litres, P in bar]
• 8.314 (L kPa / mol K) [V in Litres, P in kilopascals]
• 8.314 (J / mol K) [Determination of energy]
• 8.314 (kg m^2 / s^2 mol K) [Molecular speed, mass in kg]
• 8.314 * 10 ^3 (g m^2 / s^2 mol K) [Molecular speed, mass in g]