What is the volume of oxygen required to burn complete 45 cm³ of methane at s.t.p?

• A. 135.0 cm³
• B. 180.0 cm³
• C. 45.0 cm³
• D. 90.0 cm³

(a) The electronic configuration of five elements represented by the letters P, Q, R, S and T are indicated below.

P - 1s\(_2\)2s\(_2\)2p\(_2\)

Q 1s\(_2\)2s\(_2\)2p\(_4\)

R 1s\(_2\)2s\(_2\)2p\(_6\)

S - 1s\(_2\)2s\(_2\)2p\(_6\)3s\(_2\)

T - 1s\(_2\)2s\(_2\)2p\(_6\)3s\(_2\)3p\(_5\)

without identifying the elements, state which of them

(i) belongs to group VI in the periodic table;

(ii) is strongly metallic in character;

(iii) readily ionizes by gaining one electron;

(iv) contains two unpaired electrons in the ground state atom

(v) readily loses two electrons during chemical bonding

(vi) Does not paricipates in chemical reactions?

(vii) is an s-block element.

(b)(i) Copy and complete the table below as appropriate

(ii) Give the reason why atomic radius increases down a group in the periodic table but decreases from left to right in a period.

(c)(i) What is meant by the half-life of a radioactive element?

(ii) The nuclide \(^{210}_{84}PO\) loses an alpha 4° particle to form lead. Write an equation for the reaction.

(d) State the type of chemical bonding which accounts for each of the following observations:

(i) Chlorine exists as discrete molecules

(ii) Sodium chloride dissolves readily in water;

(iii) CuSO\(_{4(aq)}\) forms a deep blue complex ion with excess NH\(_{3(aq)}\)

When an element can exist in two or more forms in the same physical state, the element is said to exhibit?

• A. Isotophy
• B. Isomerism
• C. Allotropy
• D. Hygroscopy

The oxidation state of S in Ca(HSO\(_3\))\(_2\) is _______

• A) +2
• B) -2
• C) +4
• D) -4

The components of universal indicator solution can best be separated by

• A. chromatography
• B. filtration
• C. evaporation
• D. crystallization

A blue litmus paper turns red when dipped into a solution. What does this indicate about the solution?

• A. The solution is basic
• B. The solution is neutral
• C. The solution is acidic
• D. The litmus paper is faulty

The existence of two or more forms of the same element in the same physical state is known as.

• A) Allotropy
• B) Resonance
• C) Hybridization
• D) Isotopy

Which of the following organic compounds would decolourize bromie water?

• A. Benzene
• B. Cyclobutane
• C. Hexane
• D. Pentane

2SO₂(g) + O₂(g) ↔ 2SO₃(g) ΔH = -189 kJ mol-1 The equilibrium constant for the reaction above is increased by

• A. Increasing the temperature of the system
• B. Increase the pressure of the system
• C. The addition of a catalyst to the system
• D. Increasing the surface area of the vessel

The compound below exhibits

• A) geometric isomerism
• B) optical isomerism
• C) structural isomerism
• D) positional isomerism