The rate of a reaction usually decrease in the concentration of reactants because

• A. kinetic energy decrease
• B. temperature increase
• C. speed increases
• D. reactants collision decrease

How many moles of H₂SO₄ are there in 50 cm³ of 0.108 mol dm³ solution of the acid?

• A. 5.4x 10
• B. 5.4 x 10^-3
• C. 5.4 x 10^-2
• D. 5.4x 10^-1

(a) The electronic configurations of atoms of elements A, B, C and D are given as follows: A. Is\(^2\)2s\(^2\)2p\(^2\); B. 1s\(^2\)2s\(^2\)2sp\(^1\) ; C. 1s\(^2\)2s\(^2\) 2p\(^1\) ; D. 1s\(^2\) 2s\(^2\)

(I) Arrange the elements in order of increasing atomic size, giving reasons

(ii) State which of the elements I. is divalent II. contains atoms with two unpaired electrons in the grouped state. Ill, readily loses one electron from its atom during chemical bonding IV. belongs to group Ill in the Periodic Table.

(b)(i) State one difference between electrovalent and covalent bonds.

(ii) Name two other bonds apart from the ones in (b)(i) above which bind atoms and molecules together.

(iii) State two characteristics of a covalent compound.

(c)(i) What is isotopy?

(ii) Illustrate with suitable example

(iii) Two isotopes of Z with mass numbers 18 and 20 are in the ratio 1:2 Determine the relative atomic mass of Z.

(d)(i) Which of the following elements: calcium, fluorine, iodine neon, magnesium and helium are I. halogens II. noble gases Ill. alkaline earth metals.

(ii) Write a balanced equation for the bombardment of \(^7_3Li\) with protons to produce \(^8_4\beta\) and \(\gamma\)-rays

(iii) State one use of radioactive isotopes.

A given mass of gas occupies 2 dm3 at 300k. At what temperature will its volume be doubled keeping the pressure constant?

• A. 400 k
• B. 480 k
• C. 550 k
• D. 600 k

Which of the following is an alloy of mercury?

• A. Stainless steel
• B. Soft solder
• C. Coinage bronze
• D. Amalgam

Due to the high reactivity of sodium, it is usually stored under

• A) water
• B) mercury
• C) paraffin
• D) phenol

The metal used to recover copper from a solution of copper sulphate is?

• A. Na
• B. Ag
• C. Hg
• D. Fe

When a reaction is endothermic,

• A. Enthalpy change, ΔH is negative
• B. Heat content of a product is less than the heat content of a reactant
• C. Heat content of reactants is less than the heat content of product
• D. The reaction is non-spontaneous

Which of the following electrons configurations correctly represents an inert element?

• A. 1s22s22p4
• B. 1s22s22p63s2
• C. 1s22s22p63s23p4
• D. 1s22s22p6

The phenomenon whereby sodium trioxocarbonate (IV) decahydrate loses some of its water of crystallization on exposure to the atmosphere is known as?

• A. deliquescene
• B. hygroscopy
• C. effervescence
• D. efflorescence