Addition of charcoal to the filter bed of sand during water treatment for township supply is to?

• A. prevent goiter
• B. prevent tooth decay
• C. remove odour
• D. kill germs

Which of the following oxides is ionic?

• A. P₄O₁₀
• B. MgO
• C. Al₂O₃
• D. SO₂

What is the empirical formula of a hydrocarbon containing 0.160 moles of carbon and 0.640 moles of hydrogen

• A. CH₂
• B. CH₃
• C. CH₄
• D. C₂H₄

What does X atand for in the following expression? X = Log(10)(H⁺)

• A. Enthalpy change (ΔH)
• B. Equilibrium constant (K)
• C. Solubility product
• D. Degree of acidity (pH)

Which of the following metals would readily displace hydrogen from steam?

• A. Copper
• B. Lead
• C. Magnesium
• D. Silver

200 cm³ of air was passed over heated copper in a syringe several times to produce copper (II) oxide. When cooled, the final volume of air recorded was 158 cm³ . Estimate the percentage of oxygen in the air.

• A) 31%
• B) 27%
• C) 21%
• D) 19%

Chlorine gas is prepared in the laboratory by

• A. adding concentrated hydrochloric acid to solid manganese (IV) oxide
• B. aciding concentrated tetraoxosulphate (VI) acid to solid sodium chloride
• C. dropping concentrated hydrochloric acid onto potassium tetraoxomanganate (VI) crystals
• D. aciding concentrated tetraoxosulphate (VI) acid to hydrochloric acid

Which of the following quantities is the same for one mole of Br₂(l) and one mole of He(g)?

• A. Number of molecules
• B. Number of atoms
• C. Total mass of the particles
• D. Volume occupied at s.t.p

Which of the following gases will have the highest rate of diffusion under the same conditions? (H = 1, C =12, O = 16, S = 32, CI = 35.5)

• A. O₂
• B. CI₂
• C. HCI
• D. H₂S

What does ∆H represent in the following equation ? Cl(g) + e^-1 → CI^- (g); ΔH = - 363 kJmol^-1

• A. lonization energy
• B. Electron affinity
• C. Dissociation energy
• D. Heat of atomization