JAMB Chemistry 2012 Past Questions

Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid?

How many atoms are present in 6.0g of magnesium?
[Mg = 24, N_A = 6.02 x 10²³ mol^-1]

50 cm³ of gas was collected over water at 10^oC and 765 mm Hg. Calculate the volume of the gas at s.t.p. if the saturated vapour pressure of water at 10 ^oC is 5mm Hg

An increase in the pressure exerted on gas at a constant temperature results in

2H_2(g) + O_2(g) → 2H₂ O_(g)
In the reaction above, what volume of hydrogen would be left over when 300 cm³ of oxygen and 1000 cm³ of hydrogen are exploded in a sealed tube?

l . Evaporation. ll. Sublimation. lll. Diffusion. IV. Brownian motion.
Which of the above can correctly be listed as evidences for the particulate nature of matter?

If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form?

A hydrogen atom which has lost an electron contains

The electronic configuration of Mg ²⁺ is

Group VII elements are

Which of the following is used to study the arrangement of particles in crystal lattices?

I. It has a varied composition from one place to another. ll. it constituents can be separated by physical means
lll. It contains unreactive noble gases
which of the above shows that air is a mixture?

The chemicals used to soften hard water involves the addition of

Chlorination of water for town supply is carried out to

The solubilites of different solutes in a given solvent can be compared by

Potassium trioxochlorate (V)has a solubility of 1.5 mol dm ^-3 at 45 ^oC.On cooling this solution to a temperature of 20 ^oC, the solubility was found to be 0.5 mol dm ^-3. What mass of KCIO ₃ was crystalized out?
[K = 39, Cl = 35.5 O =16]

Which of the following pollutants is associated with brain damage?

Which of the following will produce a solution with pH less than 7 at equivalent point?

The number of hydroxonium ions produced by one molecule of an acid in aqueous solution is its

During a titration experiment, 0.05 moles of carbon (lV) oxide is liberated. What is the volume of gas liberated?

A major factor considered in selecting a suitable method for preparing a simple salt is its

The oxidation number of boron in NaBH ₄ is

2Na ₂ O _2(s) + 2H ₂ O ₂₍₁₎ → 4 NaOH_(s) +O_2(s)
The substance that is oxidized in the reaction above is

A metal M displaces zinc from ZnCl, solution, solution
This shows that

CO_(g) + H₂ O_(g) → CO_2(g) + H_2(g)
Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO_2(g), H₂O_(g) and CO_(g) and CO_(g) in KJ mol ^-1 are - 394 -242 and - 110 respectively.

An increase in entropy can best be illustrated by

The highest rate of production of carbon (lV) oxide can be achieved using

A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be

Which of the following gases has a characteristic pungent smell, turns red litmus paper blue and forms dense white fumes with hydrogen chloride gas?

Commercial bleaching can be carried out using

Mineral acids are usually added to commercial hydrogen peroxide to

Which of the following compounds will burn with a brick-red colour in a non-luminous Bunsen flame?

The purest from of iron which contains only about 0.1% carbon is

A common characteristic between zinc and the other transition elements is the ability to

Which of the following metals is the least reactive?

Geometric isomerism can exist in

Alkanals can be distinguished from alkanones by the reaction with

The isomers of C₃H₈O ARE

Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y?

A compound contains 40.0% C, 6.7% H 53.3% O. If the molecular mass of the compound is 180, its molecular formula is [C =12, H =1,O]

The saponification of an alkanoate to produce soap and alkanol involves

2 - methyl propan -2- ol is an example of a

Ethanol reacts with concentrated tetraoxosulphate (V) acid at a temperature above 170 ^oC to form

An example of oxidation - reduction enzyme is