Chemistry JAMB, WAEC, NECO AND NABTEB Official Past Questions

a. Describe how iron and aluminum reacts with each of the following substances: i.  dilute \(H_2SO_4\); ii.   dilute \(HNO_3\)

bi. Write an equation for the burning of sulphur in air.

ii. Name the catalyst used in the contact process.

iii. In the contact process, why is an excess of air used?

iv. Why is it necessary to cool the catalyst used in 5(b)(ii)?

v. Give a reason why the air used in the contact process needs to be as clean as possible.

vi. State two reasons why SO2 should not be discharged into the atmosphere.

ci. State the reagents and conditions used in the laboratory preparation of chlorine.

ii. State two uses of chlorine.

di. Name the drying agents for each of the following gases: 1. Hydrogen; 

i2.  sulphur (IV) oxide; 

i3. Ammonia.

ii1. State the components of the following
      Bronze;  ii2. Brass.

a. Starting with calcium chloride, describe briefly how a solid sample of calcium trioxocarbonate (IV) can be prepared in the laboratory.

b. With relevant equations outline the procedure for the purification of impure copper.

c. Copper reacts with concentrated trioxonitrate (V) acid:  i. write a balanced chemical equation for the reaction;

ii. state what would be observed in the reaction,

iii. state why the copper is oxidized;

iv. an excess of copper is added to 25.0 \(cm^3\) of 16.0 mol \(dm^3\) \(HNO_3\). Calculate the volume of the gas formed at s.t.p. [H=1.0, N=14.0, O= 16.0, Cu=63.0; Molar volume of gas at .s.t.p.=22.4 \(dm^3\)]

di. Pure \(HNO_3\), is a colourless liquid but when exposed to air, it turns yellowish-brown in colour. Explain briefly this observation.

ii. Write a balanced equation for the laboratory preparation of hydrogen trioxonitrate (V) acid.

a. A compound contains 52.2% C, 13.1 % H and Oxygen only. The vapour density of the compound is 23.
    Determine i. its empirical formula; ii. its molecular formula,  [H=1.0, C=12.0, O= 16.0]

iii1). The compound reacts with sodium metal to produce hydrogen gas and when warmed with acidified \(KMnO_{4(aq)}\) gives a solution that turns from purple to colorless. It also forms a sweet-smelling liquid when heated with ethanoic acid  in the presence of concentrated \(H_2SO_4\)
 name the functional group present in the compound; iii2). draw the structural formula of the compound.

b. Outline the chemical equations for the production of ethanol from cooked cassava.

ci. Explain briefly why a piece of aluminum does not react with water.

ii. How can a pure sample of aluminum chloride crystals be prepared from aluminium

d. Describe how water can be separated from aqueous \(CuSO_4\)

a. In an experiment, 20.0 \(cm^3\) of a solution containing 4g/\(dm^3\) of sodium hydroxide was neutralized by 8.0 \(cm^3\) of dilute tetraoxosulphate (VI) acid: i. Write a balanced equation for the reaction;  ii. calculate the concentration of the acid in mol/ \(dm^3\)

bi. State two postulates of the Kinetic theory of gases which real gases do not obey

ii. Explain briefly why real gases do not obey the postulates stated in 2(b)(i).

c. Consider the following compound:

     Name the compound

 ii. name the two structural isomers of the compound; 

 iii. state the chemical process involved in the preparation of the compound from starch,

iv. write the chemical equation for the steps involved in the process in 2(c)(ii).

v. name two enzymes involved in the process in 2(c)(iii)

d. Explain briefly the term structural isomerism.

a. What is a transition element?

b. Consider the electron configuration of the following elements: A=2, 8,6; B=2,8,2; C=2,8,1, D=2,8,8
State the element which forms a: i. doubly charged cation; ii. soluble trioxocarbonate (IV).

c. Explain briefly why there is a general increase in the first ionization energies of the elements across the period in the periodic table.

d. Give two examples of an aliphatic compound

e. Explain briefly why alkanols are stronger bases than water.

f. State the major raw materials used in the Solvay process

g. What is geometric isomerism?

h. Give a reason why water gas is a better fuel than producer gas.

i. Define the term heat of combustion.

ji. State Faraday’s second law of electrolysis

ii. Calculate the amount of silver deposited when 10920 coulombs of electricity is passed through a solution of a silver salt.
[IF = 96500 C mol-1]

How many moles of copper would be deposited by passing 1 Faraday of electricity through a \(CuCl_2\) solution?

How many grammes of NaOH(s) would be needed to produce 100.0 cm3 of a 0.20 mol dm-3 NaOH, (aq)? [NaOH = 40.0]

Thermal cracking of alkanes usually

The relative molar mass of a gaseous hydrocarbon is 30. Determine its vapour density.

The best indicator to use for the titration of ethanoic acid with sodium hydroxide is

An example of a crystalline substance that does not possess water of crystallization is

Which of the following gases has the lowest rate of diffusion?
[H=1.0, C=12.0, N = 14.0, O= 16.0]

Isoelectronic species have the same number of

Why are \(H_2SO_4\) and \(CaCl_2\), not suitable for drying ammonia gas? They

The reduction half equation of the following reaction is:
\(Zn_{(s)} + CuSO_{4(aq)} → ZnSO_{4(aq)} + Cu_{(s)}\)

The molecule that has a non-polar covalent bond is

Petrochemistry is an example of

Which of the following elements has its valence electrons in the s-orbital?

Which of the following statements about the collision theory is correct?

An element X has two isotopes, \(^{65}X_{30}\) and \(^{66}X_{30}\) with relative abundance of 60 % and 40% respectively. The relative atomic mass of X is

Positive ions in a sea of electrons are found in