CHEMISTRY PAST QUESTION

The atoms of four elements are represented as ₂₀Q, ₁₆R, ₁₀S and ₈T Which of the elements would be unreactive?

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

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)

Metals are said to be malleable because they

Which of the following methods is suitable for the preparation of an insoluble salt?

Pauli Exclusion Principle is related to

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

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

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

What does ∆H represent in the following equation ? Cl_(g) + e- → CI- _(g); ∆H = - 363 kJ mol-¹

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

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

Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of

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

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

The crystal layers in graphite are held together by

A finely divided from of a metal burns more readily in air than the rod from because the rod has

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

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?

What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn_(s) + 2HCI_(aq) → ZnCI _2(aq) + H_2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm³ at s.t.p]

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

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 shape of a molecule of CCI₄?

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

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

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

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

In the Periodic Table, the elements that loss electrons most readily belong to

What is responsible for metallic bonding?

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]

Electrovalent compounds are characterized by

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

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

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

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

Elements which belong to the same group in the Periodic Table are characterized by

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

Aluminium is extracted from

Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy?

Chlorine atom forms CI by

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

Pipe-borne water is usually chlorinated in order to

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

Which of the following movements can be described as random motion?

Rusting of iron is an example of

Petrol consists mainly of

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?

Gas molecules are said to be perfectly elastic because

It can be concluded that gastric juice

Which of the following contains co-ordinate covalent bond?

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

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

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]

An exothermic reaction is one which involves

Chemical equilibrium is attained when

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

A radioactive solid is best stored

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

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

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

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

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

Which of the following compounds dissolves in water to give an alkaline solution?

The liquid product of the destructive distillation of coal is

Which of the following non-metals reacts most readily with metals?

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

Calcium atom ionizes by

What is oxidized in the reaction represented by the following equation? 3CU + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O

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

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

A mixture of calcium chloride and calcium trioxocarbonate (IV) in water can be separated by

When alkanols react with sodium, the ga evolved is

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

Helium is preferred to hydrogen in filling balloons because hydrogen

Which of the following compounds dissolves in water to form a solution with pH below 7?

Which of the following is not correct about oxidation number convention? The oxidation number of a/an

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

Dehydration of ethanol produces

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