When zinc is added to AgNO₃ solution, crystals of silver forms on the zinc surface. This indicates that zinc is

• A. oxidised
• B. reduced
• C. decomposed
• D. dissociated

(a) List two properties of alpha particles.

(b) X is an element which exists as an isotopic mixture containing 90% of \(^{39}_{19} X\) and 10% of \(^{41}_{19}X\).

(i) How many neutrons are present in the isotope \(^{41}_{19}X\)?

(ii) Calculate the mean relative atomic mass of X.

A metal X forms two chlorides with the formulae XCI2 and XCI3. Where is X in the Periodic Table? What type of bonding exists between X and chlorine in each of the chlorides?

• A. metallic bonding
• B. ionic bonding
• C. covalent bonding
• D. dative bonding

Which of the following statements is true of the molecules of a gas under ideal conditions? The molecules

• A. move at random
• B. undergo inelastic collisions
• C. attract each other
• D. occupy a large volume

Methanol is obtained from wood by

• A. esterification
• B. bacterial decomposition
• C. combustion
• D. destructive distillation

Which of the following pairs of gases are pollutants from car exhaust?

• A. Nitrogen(II) oxide and Carbon(IV) oxide
• B. Carbon(IV) oxide and Nitrogen
• C. Carbon(II) oxide and Sulphur(IV) oxide
• D. Carbon(II) oxide and oxygen

which of the following is/are manufactured by electrolysis except?

• A. calcium
• B. chlorine
• C. aluminium
• D. iron

Helium is often used in observation balloons because it is?

• A. light and combustible
• B. light and non-combustible
• C. heavy and combustible
• D. heavy and non-combustible

When NH₄CI was dissolved in water, the container was cold to touch. This implies that

• A. the process is endothermic
• B. the process is exothermic
• C. NH₄CI is highly soluble in water
• D. NH₄CI forms a saturated solution

The property used in obtaining oxygen and nitrogen industrially from air is the?

• A. boiling point
• B. density
• C. rate of diffusion
• D. solubility