(i) Number of neutrons -4 1

ii)

(a) Liquid R-Water. 1

(c) It is insoluble in water. 1

(i) Dehydration.1

(ii) In the manufacture of margarine/hardening of oils. 1

iii)

HCl is covalent and dissolves in1 methylbenzene but does not ionise. Addition of water causes HCl to ionise H⁺ ions ½formed react with carbonate to produce carbon (iv) oxide gas.½

(a) B –Calcium hydroxide

(b) To prevent the water form ‘’sucking back’’ into the flask by providing a large surface area for absorption.

(c) A little of the dissolved gas combine with water to form ions

the solutions. It’s alkaline properties.

a)

b)

Boiling point increases from fluorine to Bromine.1This is because the strength of Van der Waals forces increase with molecules size from fluorine to Bromine. 1

(a)The energy change in converting reactants the products is the same regardless of the route by which the chemical change occurs.1

(i) G-Hydrogen chloride.1

B-Chlorine1

(ii) To oxidise HCL_g to chlorine.1

(a) Potassium bromide crystals½/KBr

b)

(c) Fractional crystallisation.1

Add water to the mixture½ and stir sodium carbonate dissolves½but 3 CaCO does not filter.½.Heat½the filtrate to saturation½ point and then let it cool½ to obtain crystals.

(a) Graham’s Law:

Under the same conditions of temperature and pressure, the rate of diffusion of a gas is inversely proportional to the square root of its density

b)

(a) Propan-l-ol 1and ethanoic acid1

(b) B.½ Does not form scum½ with water containing calcium ions hence lathers easily

U-Sodium hydrogen carbonate/potassium hydrogen carbonate.1

V-Sodium carbonate/potassium carbonate..1

Si=2.8.4 Cl=2.8.7

a)

(b) It sublimes.1

(c) To prevent the moisture from entering the flask since 3 FeCl₃ is deliquescent.

(ii) At point W the alkali is fully dissociated.½ As the acid is added, the hydroxyl ions are neutralised by the hydrogen ions from the acid forming water. The conductivity of the solution decreases½ as more OH are removed from the solution. At point X all the hydroxyl ions have been removed and the solution is neutral.½The conductivity is not zero because of the presence of sodium and sulphate ions. Conductivity starts increasing due to accumulation of the hydrogen ions in the solution.½

(a) It is a strong acid. The pH value decreases from 10 to 2when added to urea which is basic.

(b) P and R ½ zinc hydroxide is an amphoteric hydroxide.½

Used in metrological balloons/sea diving and mountaineering.1