1. States of matter

1.1 Solids, liquids and gases

1.2 Diffusion

2. Atoms, elements and compounds

2.1 Elements, compounds and mixtures

2.2 Atomic structure and the Periodic Table

2.3 Isotopes

2.4 Ions and ionic bonds

2.5 Simple molecules and covalent bonds

2.6 Giant covalent structures

2.7 Metallic bonding

3. Stoichiometry

3.1 Formulae

3.2 Relative masses of atoms and molecules

3.3 The mole and the Avogadro constant

4. Electrochemistry

4.1 Electrolysis

4.2 Hydrogen–oxygen fuel cells

5. Chemical energetics

5.1 Exothermic and endothermic reactions

6. Chemical reactions

6.1 Physical and chemical changes

6.2 Rate of reaction

6.3 Reversible reactions and equilibrium

6.4 Redox

7. Acids, bases and salts

7.1 The characteristic properties of acids and bases

7.2 Oxides

7.3 Preparation of salts

8. The Periodic Table

8.1 Arrangement of elements

8.2 Group I properties

8.3 Group VII properties

8.4 Transition elements

8.5 Noble gases

9. Metals

9.1 Properties of metals

9.2 Uses of metals

9.3 Alloys and their properties

9.4 Reactivity series

9.5 Corrosion of metals

9.6 Extraction of metals

10. Chemistry of the environment

10.1 Water

10.2 Fertilisers

10.3 Air quality and climate

11. Organic chemistry

11.1 Formulae, functional groups and terminology

11.2 Naming organic compounds

11.3 Fuels

11.4 Alkanes

11.5 Alkenes

11.6 Alcohols

11.7 Carboxylic acids

11.8 Polymers

12. Experimental techniques and chemical analysis

12.1 Experimental design

12.2 Acid–base titrations

12.3 Chromatography

12.4 Separation and purification

12.5 Identification of ions and gases

IGCSE Chemistry 1.2 Diffusion Question Bank

[Maximum number: 1]

An experiment is set up as shown.

After several minutes, a white ring of ammonium chloride appears as shown.

Which statement explains the observation after several minutes?

Ammonia gas diffuses faster than hydrogen chloride gas because its molecules have a lower molecular mass.

Ammonia gas diffuses faster than hydrogen chloride gas because its molecules have a higher molecular mass.

Ammonia gas diffuses slower than hydrogen chloride gas because its molecules have a lower molecular mass.

Ammonia gas diffuses slower than hydrogen chloride gas because its molecules have a higher molecular mass.

[Maximum number: 1]

A student investigated the diffusion of ammonia gas, $\mathrm{NH}_{3}$ , and hydrogen chloride gas, HC l.
Two sets of apparatus were set up as shown at room temperature and pressure.

apparatus 1

apparatus 2

The damp red litmus paper in apparatus 1 changed colour after 30 seconds.
How long does it take for the damp blue litmus paper to change colour in apparatus 2 ?

64 seconds

30 seconds

21 seconds

The blue litmus paper would not change colour.

[Maximum number: 1]

Oxygen and fluorine are gaseous elements next to each other in the Periodic Table.
Under the same conditions of temperature and pressure, oxygen diffuses 1 than fluorine because its 2 is less than that of fluorine.

Which words correctly complete gaps 1 and 2?

faster

molecular mass

faster

reactivity

slower

molecular mass

slower

reactivity

[Maximum number: 1]

Which statement explains why ammonia gas, $\mathrm{NH}_{3}$ , diffuses at a faster rate than hydrogen chloride gas, HCl ?

Ammonia expands to occupy all of the space available.

Ammonia has a smaller relative molecular mass than hydrogen chloride.

Ammonia is an alkali and hydrogen chloride is an acid.

Ammonia molecules diffuse in all directions at the same time. 22.00 g of powdered calcium carbonate is added to $50.0 \mathrm{~cm}^{3}$ of hydrochloric acid. Which apparatus is used to measure the calcium carbonate and the hydrochloric acid?

calcium carbonate

hydrochloric acid

balance

burette

balance

thermometer

pipette

burette

pipette

thermometer

[Maximum number: 1]

Samples of four gases are released in a room at the same time.
The gases are carbon dioxide, $\mathrm{CO}_{2}$ , hydrogen chloride, HCl , hydrogen sulfide, $\mathrm{H}_{2} \mathrm{~S}$ , and nitrogen dioxide, $\mathrm{NO}_{2}$ .

Which gas diffuses fastest?

carbon dioxide

hydrogen chloride

hydrogen sulfide

nitrogen dioxide

[Maximum number: 1]

Which gas has the slowest rate of diffusion?

$\mathrm{H}_{2}$

$\mathrm{NH}_{3}$

$\mathrm{CH}_{4}$

$\mathrm{CO}_{2}$

[Maximum number: 1]

Which gas diffuses the most slowly?

$\mathrm{CH}_{4}$

$\mathrm{CO}_{2}$

$\mathrm{H}_{2}$

$\mathrm{NH}_{3}$

[Maximum number: 1]

'Particles moving very slowly from an area of higher concentration to an area of lower concentration.'

Which process is being described?

a liquid being frozen

a solid melting

a substance diffusing through a liquid

a substance diffusing through the air

[Maximum number: 1]

The diagram shows the result of dropping a purple crystal into water.

Which processes take place in this experiment?

chemical

reaction

diffusing

dissolving

$\checkmark$

[Maximum number: 1]

Small crystals of purple $\mathrm{KMnO}_{4}\left(M_{\mathrm{r}}=158\right)$ and orange $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\left(M_{\mathrm{r}}=294\right)$ were placed at the centres of separate petri dishes filled with agar jelly. They were left to stand under the same physical conditions.

After some time, the colour of each substance had spread out as shown.