The energy value of petrol can be determined by a

• A. bomb calorimeter
• B. catalytic cracker
• C. fractionating column
• D. thermometer

A solid that absorbs water from he atmosphere and forms an aqueous solution is?

• A. hydrophilic
• B. efforescent
• C. deliquescent
• D. hygroscopic

(a) Define each of the following terms:

(i) ion; (ii) isotopes.

(b)(i) Consider the:element \(_{12}\)Mg and \(_{3}\)Al

I. Write the electron configuration of each element. II. Explain briefly why the first ionization energy of \(_{12}\)Mg is greater than that of \(_{13}\)Al.

(ii) Write the formulae of three different oxides of period 3 elements that react with water.

(c)(i) What are allotropes?

(ii) Name the two crystalline allotropes of carbon.

(iii) Give one industrial use of each allotrope named in (c)(ii).

(d) On warming crystals of sodium chloride with concentrated tetraoxosulphate (VI) acid, a gas was evolved.

(i) List two physical properties of the gas produced.

(ii) Write a balanced equation for the reaction.

(e) A certain chip W used in a circuit of a microcomputer has a mass of 5.68mg. Calculate the amount of W in the microcomputer. [ W = 28 gmol\(^{-1}\) ].

Which of the following reactions is not feasible?

• A. Cl₂ + 2Kl → 2KCI + I₂
• B. Cl₂ + 2NaF → 2NaCI + F₂
• C. Zn + CuCI₂ ZnCl₂ + Cu
• D. Zn + 2AgNO₃ → Zn(NO₃)₂ + 2Ag

X + Y → Z. The rate equation for the chemical reaction above is ((-Δ[x])/Δt) = K[X]2[Y]. The overall order of the reaction is

• A. 0.0
• B. 1.0
• C. 2.0
• D. 3.09

In which of the following are radioactive isotopes used?

• A) Scientific research
• B) Dating techniques
• C) Treatment of cancer
• D) All of the above

A. number of the collisions between the gas molecules and the walls of the container

• A. bleaches damp blue litmus paper
• B. forms a white preciptate with AgNO3(aq)
• C. forms a white precipitate with BaCI2(aq)
• D. turns moist red litmus paper blue

The mass of one Avogadro number of helium atoms is?

• A. 1.00gram
• B. 4.00gram
• C. 8.00gram
• D. 6.00gram

Which of the following is true of a sample of hydrogen gas whose mass is 4.00g under a pressure of 2atm and a temperature of 27°C? [H = 1, R = 0.082 lit atm. Mol^?1 k^?1 ]

• A) Its volume is 24.6 litres
• B) It contains 6.02
• C) It exists as atoms because of temperature
• D) None of the above

When element₂₀A combines with element₈Y,

• A. a covalent compound, AY is formed
• B. an ionic compound AY is formed
• C. an ionic compound, A2Y is formed
• D. a covalent compound, AY2 is formed