Chemistry JAMB, WAEC, NECO AND NABTEB Official Past Questions

In the reactions

(I) H₂ (g) + 1/2O₂(g) → H₂O(l); ∆H = -286 KJ

(II) C(s) + O₂g) → CO₂ (g); ∆H = -406 KJ the equations imply that

Solutions X, Y, and Z have PH values 3.0. 5. 0 and 9. 0 respectively. Which of the following statements is correct?

An element is electronegative if

Crude petroleum pollutant usually seen on some Nigerian creeks and waterways can be dispersed or removed by

Which of the following happens during the electrolysis of molten sodium chloride?

Sodium sulphate decahydrate (Na₂SO₄.10 H₂O) on exposure to air loses all its water of crystallization.
The process of loss is known as

A piece of burning sulphur will continue to burn in a gas jar of oxygen to give misty fumes which readily dissolved in water. The resulting liquid is

How many isomeric forms are there for the molecular formula C₃H₆Br₂?

The correct name of the compound with the above structural formula is

In the reaction Fe + Cu²⁺ \(\to\) Fe²⁺ + Cu,iron displaces copper ions to from copper. This is due to the fact that

In which of the following processes is iron being oxidized?

1 Fe + H₂SO₄ → FeSO₄ +H₂

2 FeSO₄ + H₂S → FeS + H₂SO₄

3 2FeCI₂ + Cl₂ → 2FeCl₃

4 2FeCl₃ + SnCl₂ + → 2FeCl₂ + SnCl₄

In the reaction M + N P;∆H = + QKJ. Which of the following would increase the concentration of the product?

The colour imparted to a flame by calcuium ion is

Which of the following relationships between the pressure P, the volume V and the temperature T, represents an ideal gas behaviour?

A mixture of common salt, ammonium chloride and barium sulphate can best be separated by

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.

Reaction of X with yeast forms the basis of the

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.

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.

Compound W is

The three-dimensional shape of methane is

Some copper (ll) sulphate pentahydrate (CuSO₄ 5H₂O), was heated at 120 ^oC with the following results. Wt of crucible = 10.00 g; Wt of crucible + CuSO₄ 5H₂O =14.98g; Wt of crucible + residue = 13.54 g. How many molecules of water of crystalization were lost?

[H = 1, Cu = 63.5, O = 16, S = 32]

If an element has the electronic configuration 1s ² 2s² 2p³ 3s² 3p⁴, it is