RevisionDojo

S1.5 Ideal gases - IB Questionbank | RevisionDojo

Practice S1.5 Ideal gases with authentic IB Chemistry exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like atomic structure, chemical reactions, and organic chemistry. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.

Paper

Level

Question 1

SLPaper 2

A student collects hydrogen gas produced by the reaction of magnesium with hydrochloric acid. The volume of gas collected is $500 \mathrm{~cm}^3$ at 298 K and 101 kPa .

Explain why the volume of hydrogen gas collected increases when the temperature rises, assuming pressure remains constant.

[2]

Calculate the amount in moles of hydrogen gas collected.

[2]

Question 2

SLPaper 2

A student collects a gas sample in a syringe after a reaction between magnesium and hydrochloric acid. The volume of gas collected is $125\ \mathrm{cm^3}$ at $298\ \mathrm{K}$ and $101\ \mathrm{kPa}$ .

Convert the gas volume to $\mathrm{m^3}$ for use in calculations.

[1]

Use the ideal gas equation to calculate the amount in moles of gas collected.

[2]

Magnesium reacts with excess HCl according to:

$Mg(s)+2HCl(aq)\to MgCl_2(aq)+H_2(g)$

Determine the mass of magnesium that would have been used to produce this amount of gas.

[2]

State one assumption made when using the ideal gas law in this experiment.

[1]

Question 3

SLPaper 2

A chemistry student heats a gas sample in a sealed container. Initially, the gas occupies a volume of $1.00 \times 10^{-3} \mathrm{~m}^3$ at 290 K and pressure of $1.00 \times 10^5 \mathrm{~Pa}$ .

Explain what happens to the pressure of the gas if the temperature increases to 350 K , assuming the volume remains constant.

[2]

Calculate the number of moles of gas in the container before heating.

[2]

Question 4

SLPaper 2

An oxygen cylinder used in hospitals contains oxygen gas at a pressure of $4.00 \times 10^6\ \mathrm{Pa}$ and a temperature of $295\ \mathrm{K}$ . The internal volume of the cylinder is $10.0\ \mathrm{dm^3}$ .

State the assumptions made about the particles of an ideal gas.

[2]

Calculate the number of moles of oxygen gas in the cylinder.

[2]

Calculate the mass of oxygen in the cylinder.

[1]

The cylinder is used in an ambulance and left outside in cold weather. Predict and explain the effect of a drop in temperature on the pressure of the gas, assuming constant volume.

[2]

Explain why high pressure in a real gas may lead to deviations from ideal gas behavior.

[2]

Question 5

SLPaper 2

A weather balloon is filled with helium gas and released into the atmosphere. At ground level, the balloon contains $2.00\ \mathrm{mol}$ of helium at $300\ \mathrm{K}$ and $1.00 \times 10^5\ \mathrm{Pa}$ .

Calculate the initial volume of the helium gas.

[2]

State two reasons why helium approximates ideal gas behavior more closely than oxygen.

[2]

As the balloon rises, the external pressure drops to $3.00 \times 10^4\ \mathrm{Pa}$ and the temperature decreases to $250\ \mathrm{K}$ . Calculate the new volume of the gas, assuming no helium escapes.

[2]

Suggest and explain one assumption made in the calculation in part (c) that may not hold in real atmospheric conditions.

[2]

The ideal gas equation is derived from kinetic theory. Explain how two of its postulates are violated under high pressure or low temperature.

[2]

Question 6

HLPaper 1A

What volume of carbon dioxide, $CO_2$ (g), can be obtained by reacting 1 $dm^3$ of methane, $CH_4$ (g), with 1 $dm^3$ of oxygen, $O_2$ (g)?

$CH_4 (g) + 2O_2 (g) → CO_2 (g) + 2H_2O (l)$

Question 7

SLPaper 1A

Which sample contains the fewest moles of HCl?

$N_A = 6.02 × 10^{23} \ mol^{–1}.$

Molar volume of an ideal gas at $STP = 22.7 \ dm^3 \ mol^{–1}$ .

Question 8

SLPaper 1A

What is the volume of gas when the pressure on 100 $\mathrm{cm}^3$ of gas is changed from 800 $\mathrm{kPa}$ to 200 $\mathrm{kPa}$ at constant temperature?

Question 9

SLPaper 1A

How many grams of sodium azide, $NaN_3$ , are needed to produce 68.1 $dm^3$ of nitrogen gas, $N_2$ (g), at standard temperature and pressure (STP)?

$2NaN_3 (s) → 3N_2 (g) + 2Na (s)$

Question 10

SLPaper 1A

Which volume of ethane gas, in $\mathrm{cm}^3$ , will produce 40 $\mathrm{cm}^3$ of carbon dioxide gas when mixed with 140 $\mathrm{cm}^3$ of oxygen gas, assuming the reaction goes to completion?

$2C_2H_6( )g+7O_2( g)→4CO_2( g)+6H_2O( g)$

Structure 1. Models of the particulate nature of matter5 subtopics

Structure 2. Models of bonding and structure4 subtopics

Structure 3. Classification of matter2 subtopics

Reactivity 1. What drives chemical reactions?4 subtopics

Reactivity 2. How much, how fast and how far?3 subtopics

Reactivity 3. What are the mechanisms of chemical change?4 subtopics

S1.5 Ideal gases Questionbank