Syllabus Edition

First teaching 2023

First exams 2025

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Ideal Gases (HL IB Chemistry)

Topic Questions

11 mark

For an ideal gas at constant pressure and temperature, which diagram shows the correct graph of pV against n?1-2-e-q7-ib-chemistry-mcqs

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21 mark

The Mr value of a gas can be calculated from the ideal gas equation.

Which expression will give the value of Mr for a sample of a gas of mass m in grams?

  • M subscript r italic equals italic space fraction numerator m R T over denominator p V end fraction

  • M subscript r italic space italic equals italic space fraction numerator p V R T over denominator m end fraction

  • M subscript r italic space italic equals italic space fraction numerator m p V over denominator R T end fraction

  • M subscript r italic space italic equals italic space fraction numerator p V over denominator m R T end fraction

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31 mark

Which of the following least resembles an ideal gas at room temperature?

  • helium

  • ammonia

  • carbon dioxide

  • hydrogen

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41 mark

The ideal gas equation below summarises the gas laws.

pV = nRT

Which statement below is correct?

  • there exist intermolecular forces of attraction between gas molecules  

  • ideal gas molecules will collide inelastically upon impact with each other 

  • one mole of an ideal gas occupies the same volume under the same conditions of temperature and pressure 

  • the volume of a given mass of an ideal gas is doubled if its temperature is raised from 25oC to 50o

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11 mark

A tube of volume 0.3 dm3 is filled with nitrogen at 27 oC and 100 kPa, the mass of the tube increases by 1.01×10-3 kg.

Assume the gas is obeying the ideal gas laws.

What is the mass of this sample of gas?

  • 4.77 x 10-3

  • 3.37 x 10-4

  • 2.97

  • 3.37 x 10-1

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21 mark

The glass containers X and Y are connected by a closed valve.1-2-h-q11-ib-chemistry-mcqs

X contains pure CO2 gas at 25 °C and a pressure of 1 × 105 Pa. Container Y has been evacuated prior to the experiment and has a volume three times bigger than container X.

During the experiment, the valve is opened, and the temperature of the whole apparatus is raised to 160 °C.

What is the final pressure in the system?

  • 160000

  • 193736

  • 48434

  • 36326

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31 mark

Iodine is a shiny, black solid. Solid iodine sublimes easily when heated to produce a purple vapour.

A block of solid iodine is put into a closed container and completely sublimed to produce 1.3 dm3 of iodine vapour. It is then kept at a constant temperature and pressure of 100kPa. 

The empty container had a mass of 3.22 g and when iodine was added the mass increased to 9.57 g. (Mr I2= 253.8) 

If iodine vapour acts as an ideal gas, what is the approximate temperature of the iodine vapour?

  • 3.91 x 10-1 

  • 6.23 x 102

  • 6.23 x 105

  • 6.23 x 10-1

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11 mark

An experiment is conducted to calculate the Mr of an unknown gas of known mass.

Measurements of pressure, volume and temperature are taken during the experiment.

Which conditions of temperature and pressure would give the most accurate value of Mr?

 

pressure

temperature

A

low

high

B

low

low

C

high

high

D

high

low

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21 mark

0.96 g of hydrogen gas is contained in a sealed vessel of volume of 7.0 × 10−3 m3 at a temperature of 303 K.

Assume the gas behaves as an ideal gas.

What is the pressure of the vessel in Pa?

  • 5.85 x 10-6

  • 171 031

  • 345 482

  • 325 128

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31 mark

A 5370 cm3 sample of oxygen is measured at a temperature of 60°C. The pressure measured was 103,000 Pa.

Assume the gas behaves as an ideal gas.

What is the mass of the sample of oxygen?

  • 35.5

  • 6.39

  • 6.39 x 10-3 

  • 6.39 x 106

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41 mark

A sample of chlorine gas with a of mass 5.35 g has a volume of 1.247 × 10-3 m3 at a pressure of 1.00 × 105 Pa.

Assuming that the gas acts as an ideal gas, what is the temperature of the gas in K?

  • 1.13 x 10-2

  • 80.2

  • 1.13

  • 199

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51 mark

A bubble travelled up from the sea bed to the surface. Just below the surface of the sea the bubble had a volume of 200 cm3 at a pressure of 101 kPa. The temperature at the surface is the same as at the sea bed.

The pressure at the sea bed is 2020 kPa. 

What is the volume of the bubble at the sea bed?

  • 10 cm3

  • 200 cm3

  • 100 cm3

  • 1000 cm3

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61 mark

Sodium reacts with water in the equation below.

2Na (s)  +  2H2O (l)  →  2NaOH (aq)  +  H2 (g)

Which mass of sodium reacts with water to produce 960 cm3 of hydrogen gas at 100 kPa and 20 oC?

  • 0.554

  • 1.80

  • 1.81 x 106 

  • 0.906

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71 mark

When a sample of a gas is compressed at room temperature from 101kPa to 300 kPa, its volume changes from 50.0 cm3  to 17.5 cm3.

Which statement best describes why this happens?

  • the gas is behaving ideally  

  • the gas behaves non-ideally 

  • gas is absorbed on to the vessel walls

  • the gas partially liquifies  

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81 mark

What mass of methane, CH4, would occupy a volume of 3 dm 3 at 25oC and 100 kPa pressure?

  • 1943

  • 1.943 x 10-3 

  • 23.17

  • 1.943

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91 mark

Which expression gives the pressure exerted by 1.5 ×10-2 mol of carbon dioxide in a container of volume 2 dm3 at 275oC?

  • 1.71 x 107

  • 3.42 x 107

  • 3.42 x 104

  • 1.71 x 104

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