CHEMISTRY PAST QUESTIONS

Rusting of iron is an example of

Helium is preferred to hydrogen in filling balloons because hydrogen

Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode?

P _Total = F₁ + P₂ + P ₃ + .........P_n' where P _Total is the pressure of a mixture of gasses. The equation above is an expression of

Which of the following procedures is suitable for identifying the food colouring added to a pastry sample?

The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is

What is the shape of a molecule of CCI₄?

The crystal layers in graphite are held together by

Which of the following pairs of reagents recat to produce hydrogen?

Metals are said to be malleable because they

The spontaneity of a chemical reaction is determined by the change in the

Which of the following features of a human skeleton can be determined by carbon-dating?

Consider the following equation: Ag⁺ _(aq) + CI-_(aq) → Ag⁺CI- _(s) ; ∆H = _65.7 kJmol^-1. From the equation, it can be deduced that

30cm³ pf hydrogen at s.t.p combine with 20cm³ of oxygen to form steam according to the following equation 2H_2(g) + O_2(g) → 2H₂O_(g). Calculate the total volume of the gaseous mixture at the end of the reaction

Which of the following statements about ideal gases is/are correct?

I. The cohesive forces between their particles are negligible

ll. The have no definite volume but occupy the volume of their containers

III. They are not compressible

IV. Their particles collide with loss of energy

What is the function of sulphur (IV) oxide in the reaction represented by the following equation? SO _2(aq) + 2H₂S_(g) → 3S _(s) + 2H ₂O _(l)

A radioactive solid is best stored

Petrol consists mainly of

Substances which absorb water from the atmosphere without dissolving in it are said to be

Which of the following would dissolve in warm dilute H₂SO₄ without effervescence, to give a blue solution?

What is the value of x in the following equation? Cr₂O₇^2- + 14H⁺ + xe- → 2Cr³⁺ + 7H₂O

What is the oxidation number of nitrogen in AI(NO₃)₃?

Which of the following lowers the activation energy of a chemical reaction?

The liquid product of the destructive distillation of coal is

A sheet of paper is placed in the path of a beam from a radioactive source. The emissions that pass through the paper consist of

Given that the order of reactivity of four metals is P>Q>R>S, which of the following reactions is feasible?

It can be concluded that gastric juice

Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore

Which of the following increases as boiling water changes to steam?

Consider the reaction represented by the following equation: H_2(g) + 1_2(g) → 2HI_(g). The number of effective collisions of molecules of the reactants decreases as

If the solubility of KHCO₃ is 0.40 mole dm^-3

Elactrostatic force of attraction between sodium ion and halide ion is greatest in

The type of chemical bond that exists between potassium and oxygen in potassium oxide is

Which of the following properties increases down a group in the Periodic Table?

One mole of a compound M(HCO₃)₂ has a mass of 162g. Calculate the relative atomic mass of M. [H = 1, C =12, O = 16]

The presence of unpaired electrons in an atom of a transition metal gives rise to

When alkanols react with sodium, the ga evolved is

Which of the following contains co-ordinate covalent bond?

Which of the following can undergo both addition reactions and substitution reactions?

Which of the following will displace copper from a solution of copper (ll) salt?

Chlorine atom forms CI by

Gas molecules are said to be perfectly elastic because

0.10 mol dm^-3 NaCI conducts electricity better than 0.10 mol dm^-3 CH₃COOH because the solution of NaCI

What mass of copper would be deposited by a current of 1. 0 ampere passing for 965 seconds through copper (ll) tetraoxosulphate (IV) solution? [Cu = 63.5; 1F = 96500C]

How many electrons are removed from Cr^2- when it is oxidized to CrO₄^2-?

The property of calcium chloride which makes it useful as a drying agent is that it is

What is responsible for metallic bonding?

What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO₃?

An exothermic reaction is one which involves

Which of the following occurs when a solution of CuSO₄ is electrolysed using copper electrodes?

Electrovalent compounds are characterized by

Equal volumes of CO₂ cnd CO at s.t.p have the same

What is the effect of using vanadium (V) oxide as catalyst in the reaction represented by the following equation? 2SO₂ + O₂ ⇌ 2SO₃; ∆H = - xKJmol-¹

If an element with high electron affinity combines with another element with low ionization energy the bond formed will be mainly

What will be the effect of increase in pressure on the following system at equilibrium? 2NH_2(g) N_2(g) + 3H_2(g)

Which of the following substances decomposes when an electric current is passed through it?

Pauli Exclusion Principle is related to

A concentrated solution containing H⁺, Cu²⁺,OH^- and CI^- was electrolysed using platiunm electrodes which of the ions will be discharged at the cathods?

Aluminium is extracted from

A reaction is represented by the equation below. A_2(g) + B_2(g) 2AB_(g); ∆H = +X kJmol^-1 Which of the following statements about the system is correct?