Gas Laws

Question 1

Regarding the behaviour of a gas (true or false):

Behaviour deviates from that of an ideal gas as temperature and pressure fall

Answer 1

False. Behaviour deviates as temperature falls and pressure rises.

Question 2

Regarding the behaviour of a gas (true or false):

As temperature rises, if the volume is kept constant, pressure also rises

Answer 2

True. This is the third ideal gas law.

Question 3

Regarding the behaviour of a gas (true or false):

32 g of nitrous oxide would occupy a volume of 22.4 litres at standard temperature and pressure

Answer 3

False. 44 g of nitrous oxide would occupy 22.4 litres. 32 g is equivalent to one mole of oxygen not nitrous oxide.

Question 4

Regarding the behaviour of a gas (true or false):

The pressure reading on the gauge of an oxygen cylinder varies directly with the volume of available oxygen remaining

Answer 4

True. This is a refection of Boyle’s Law; PV = constant.

Question 5

Regarding the behaviour of a gas (true or false):

One litre of an ideal gas at standard temperature and pressure would contain 22.4 moles

Answer 5

False. One mole of an ideal gas at standard temperature and pressure would occupy 22.4 litres.

Question 6

Regarding oxygen (true or false):

The critical temperature of oxygen is -182°C

Answer 6

False. The critical temperature of oxygen is -119°C.

Question 7

Regarding oxygen (true or false):

Oxygen cannot be liquefied at room temperature because its critical pressure cannot be reached

Answer 7

False. Oxygen cannot be liquefied at room temperature regardless of pressure applied as it is above its critical temperature.

Question 8

Regarding oxygen (true or false):

One mole of oxygen at 1 atmosphere pressure and room temperature would occupy 22.4 litres

Answer 8

False. One mole at standard temperature (273.15 K) and 1 atmosphere pressure would occupy this volume.

Question 9

Regarding oxygen (true or false):

One mole of oxygen has a mass of 32 g

Answer 9

True

Question 10

Regarding oxygen (true or false):

The partial pressure of oxygen in room air would be approximately 101 kPa

Answer 10

False. The partial pressure of oxygen in air would be approximately 21 kPa

Question 11

Regarding the ideal gas law PV = nRT (true or false):

The unit of the ideal gas constant is in moles

Answer 11

False. The units are J K-1 mol-1.

Question 12

Regarding the ideal gas law PV = nRT (true or false):

n must always be greater than 1

Answer 12

False. n must be greater than or equal to zero.

Question 13

Regarding the ideal gas law PV = nRT (true or false):

Temperature must always be expressed in Kelvins

Answer 13

True. The Kelvin scale must be used.

Question 14

Regarding the ideal gas law PV = nRT (true or false):

Measurements must always be taken at standard temperature and pressure

Answer 14

False. Temperature and pressure are variables.

Question 15

Regarding the ideal gas law PV = nRT (true or false):

The law becomes less accurate as P rises and T falls

Answer 15

True. As temperature falls and pressure rises the gas will start to liquefy.