13 p20 n

12 p20 n

13 p22 n

15 p22 n

Secondary 4 Express Science(Chemistry) Test

1 The diagrams below show the nuclei of four different atoms.

Q R S T

Which two atoms are isotopes of each other?

A Q and S C Q and RB R and S D S and T

2 Elements X and Y combine to form the gas XY2.What are X and Y?

X YA Sodium ChlorineB Carbon HydrogenC Carbon OxygenD Hydrogen oxygen

3 Which of the following particles contains the same number of electrons as an atom of neon?

A LiB NaC Cl-D O2-

4 What happens when sodium chloride melts?

A Covalent bonds in a giant lattice are broken.B Electrons are released from atoms.C Electrostatic forces of attraction between ions are overcome.D Molecules are separated into ions.

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Keyp = protonn = neutron

5 Zinc reacts with dilute hydrochloric acid to produce a gas X.

Iron(II) carbonate reacts with dilute hydrochloric acid to produce a gas Y.

What are gases X and Y?

ABCD

Gas X Gas YHydrogen Carbon dioxideCarbon dioxide HydrogenWater vapour Carbon dioxideSulphur dioxide Carbon dioxide

6 Which reactants can be used safely to prepare sodium chloride?

A aqueous sodium sulphate and aqueous barium chlorideB aqueous sodium hydroxide and dilute hydrochloric acidC sodium and dilute hydrochloric acidD sodium oxide and concentrated hydrochloric acid

7 An acid, X, was added to a solution of the nitrate of metal Y. A dense white precipitate was formed.

What are X and Y?

Acid X Metal YA Hydrochloric CalciumB Nitric ZincC Hydrochloric SilverD Sulphuric Copper

8 Magnesium reacts with oxygen to form the ionic compound magnesium oxide.

(a) With the aid of the Periodic Table, draw a ‘dot and cross’ diagram to show the bonding in magnesium oxide.You only need to draw the outermost electrons of magnesium and of oxygen.

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[2]

(b) The physical properties of a compound are related to its structure and bonding.Magnesium oxide has an ionic lattice structure.

i. Suggest one physical property (other than electrical property) of magnesium oxide.

…………………………………………………………………………………… [1]

ii. Explain the reason why molten magnesium oxide conducts electricity.

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

…………………………………………………………………………………… [2]

(c) State whether magnesium oxide is an acidic, basic, amphoteric or neutral oxide.

…………………………………………………………………………………… [1]

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(d) Magnesium oxide reacts with dilute nitric acid to form two products. Write a balanced chemical equation for the reaction.

…………………………………………………………………………………… [1]

(e) Magnesium can also form a compound with nitrogen. Suggest the chemical formula of magnesium nitride.

……………………………………………………………………………………

(f) Write the equation for magnesium reacting with steam. [1]

[1]

……………………………………………………………………………………

9. The sea contains a low concentration of bromide ions. Bromine can be extracted from sea water by first concentrating the sea water and then bubbling chlorine through this solution.

(a) The chlorine oxidises bromide ions to bromine.

Construct a balanced ionic equation for this reaction. [1]

………………………………………………………………………………….

(b) Bromine reacts with sodium to form an ionic compound. State the chemical formula of the ionic compound. [1]

…………………………………………………………………………………

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