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 3.3 The mole and the Avogadro constant Question Bank

[Maximum number: 2]

Iron ore contains iron(III) oxide, $\mathrm{Fe}_{2} \mathrm{O}_{3}$ . A blast furnace is used to extract iron from $\mathrm{Fe}_{2} \mathrm{O}_{3}$ .
Equations for some of the reactions in the blast furnace are shown.

equation $1 \mathrm{C}+\mathrm{O}_{2} \rightarrow \mathrm{CO}_{2}$

equation $2 \mathrm{CaCO}_{3} \rightarrow \mathrm{CaO}+\mathrm{CO}_{2}$

equation $3 \quad \mathrm{CaO}+\mathrm{SiO}_{2} \rightarrow \mathrm{CaSiO}_{3}$

(a)

Iron(III) oxide, $\mathrm{Fe}_{2} \mathrm{O}_{3}$ , in iron ore is converted to iron when it reacts with carbon monoxide, CO , in the blast furnace.

[ 2 ]

(i)

Calculate the percentage by mass of iron in iron(III) oxide, $\mathrm{Fe}_{2} \mathrm{O}_{3}$ .

percentage = ...............................\% [2]

[ 2 ]

[Maximum number: 2]

This question is about elements X, Y and Z.

(a)

(i)

What is the name of the amount of any substance that contains $6.02 \times 10^{23}$ particles?

[ 1 ]

(ii)

The constant $6.02 \times 10^{23}$ has a name.

What is the name of this constant?

[ 1 ]

[Maximum number: 3]

Period 3 contains the elements sodium to argon. This question asks about the chemistry of each of the Period 3 elements or their compounds.

(a)

Sodium nitrate is a white crystalline solid. When heated it melts and the following reaction occurs.

2 \mathrm{NaNO}_{3}(\mathrm{I}) \rightarrow 2 \mathrm{NaNO}_{2}(\mathrm{I})+\mathrm{O}_{2}(\mathrm{~g})

A 3.40 g sample of sodium nitrate is heated.
Calculate the
- number of moles of $\mathrm{NaNO}_{3}$ used, mol
- number of moles of $\mathrm{O}_{2}$ formed, mol
- volume of $\mathrm{O}_{2}$ formed, in $\mathrm{dm}^{3}$ (measured at r.t.p.). $\mathrm{dm}^{3}$

[ 3 ]

[Maximum number: 1]

Which gas sample contains the smallest number of molecules?

4 g of helium

16 g of oxygen

28 g of carbon monoxide

28 g of nitrogen

[Maximum number: 1]

The concentration of a hydrochloric acid solution is $0.5 \mathrm{~mol} / \mathrm{dm}^{3}$ .
How many moles of hydrochloric acid are present in $25 \mathrm{~cm}^{3}$ of this solution?

0.0125

0.0200

12.5

20.0

[Maximum number: 1]

Which gas sample contains the most molecules?

$24 \mathrm{dm}^{3}$ of carbon dioxide, $\mathrm{CO}_{2}$

4 g of hydrogen, $\mathrm{H}_{2}$

$36 \mathrm{dm}^{3}$ of hydrogen chloride, HCl

14 g of nitrogen, $\mathrm{N}_{2}$

[Maximum number: 1]

Which gas sample has the greatest mass?

5.0 moles of $\mathrm{Cl}_{2}$

10.0 moles of $\mathrm{O}_{2}$

15.0 moles of $\mathrm{N}_{2}$

20.0 moles of $\mathrm{H}_{2}$

[Maximum number: 1]

The equation for the reaction of iron(III) oxide with carbon monoxide is shown.

\mathrm{Fe}_{2} \mathrm{O}_{3}+3 \mathrm{CO} \rightarrow 2 \mathrm{Fe}+3 \mathrm{CO}_{2}

What is the percentage yield of iron when 16.8 g of carbon monoxide reacts completely with iron(III) oxide to form 8.96 g of iron?

26.7%

40.0\%

53.3\%

80.0\%

[Maximum number: 1]

Which sample contains the largest number of molecules?

16 g of methane, $\mathrm{CH}_{4}(\mathrm{~g})$

16 g of oxygen, $\mathrm{O}_{2}(\mathrm{~g})$

16 g of phosphorus, $\mathrm{P}_{4}(\mathrm{~s})$

$16 \mathrm{dm}^{3}$ of methane at r.t.p., $\mathrm{CH}_{4}(\mathrm{~g})$

[Maximum number: 1]

A tablet contains 0.080 g of ascorbic acid ( $M_{\mathrm{r}}=176$ ).
What is the concentration of ascorbic acid when one tablet is dissolved in $200 \mathrm{~cm}^{3}$ of water?

$9.1 \times 10^{-5} \mathrm{~mol} / \mathrm{dm}^{3}$

$4.5 \times 10^{-4} \mathrm{~mol} / \mathrm{dm}^{3}$

$9.1 \times 10^{-2} \mathrm{~mol} / \mathrm{dm}^{3}$

$2.3 \times 10^{-3} \mathrm{~mol} / \mathrm{dm}^{3}$

0 selected

Question 1

Question 1(b)

Question 1(b)(i)

Question 1

Question 1(b)

Question 1(b)(iii)

Question 1(b)(iv)

Question 2

Question 2(a)

Question 7

Question 7

Question 7

Question 7

Question 7

Question 7

Question 8