Chemistry Past Questions and Answers

Some copper (ll) sulphate pentahydrate (CuSO<sub style='font-size: smaller;'>4</sub> 5H<sub style='font-size: smaller;'>2</sub>O), was heated at 120 <sup style='font-size: smaller;'>o</sup>C with the following results. Wt of crucible = 10.00 g; Wt of crucible + CuSO<sub style='font-size: smaller;'>4</sub> 5H<sub style='font-size: smaller;'>2</sub>O =14.98g; Wt of crucible + residue = 13.54 g. How many molecules of water of crystalization were lost?<br/>[H = 1, Cu = 63.5, O = 16, S = 32]

The three-dimensional shape of methane is

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.<br/>Compound W is

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.<br/>The molecular formula of X is

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.<br/>Reaction of X with yeast forms the basis of the