Ionization energy increases across the period in the periodic table because

• A. atomic number increases
• B. effective nuclear charge increases
• C. mass number decreases
• D. screening effect decreases

In which of the following compounds is the oxidation number of nitrogen equal to + 3?

• A. NO₂
• B. N₂O
• C. NO
• D. HNO₂

(a)(i) Draw and label a diagram to illustrate the preparation and collection of dry chlorine gas in the laboratory.

(ii) List two uses of chlorine.

(b)(i) Explain why river water flowing through an industrial town may be unsafe for drinking.

(ii) State the use of each of the following substances in water treatment: I. Sand, II. Chlorine, III. Calcium oxide, IV. Alum

(c)Consider the reaction represented by the following equation:

2Na\(_2\)CI\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) \(\to\) Na\(_2\)SO\(_{4(aq)}\) + 2HCI\(_{(g)}\)

Calculate the volume of HCI gas that can be obtained at s.t.p. from 5.85 g of sodium chloride. [H = 1, Na = 23, CI = 35.5, Molar volume a 22.4 dm\(^3\) at s.t.p]

(d) Give one example in each case of a (i) metal that is a liquid at room temperature. (ii) non-metal that is a iiquid at room temperature, (iii) gas at room temperature that is monatomic.

(e) State two differences between metals and nom metals with respect to their: (i) physical properties; (ii) chemical properties.

The substance that is used in the steel industry for the removal of carbon, sulphur and phosphorus impurities from pig iron is

• A) oxygen
• B) chlorine
• C) nitrogen
• D) hydrogen

When an atom gains an electron, it becomes properties

• A. chemically inactive
• B. negatively charged
• C. oxidized
• D. a cation

The substance least considered as a source of environmental pollution is

• A. Lead compounds
• B. Organophosphorous compounds
• C. Silicate minerals
• D. Uranium

What is the main environmental concern associated with sulfur dioxide emissions?

• A. Formation of acid rain
• B. Global warming potential
• C. Depletion of the stratospheric ozone
• D. Depletion of the ozone layer

Glucose can be obtained from starch by

• A. hydrogenation
• B. dissoiation
• C. hydrolysis
• D. dialysis

Mineral acids are usually added to commercial hydrogen peroxide to

• A) oxidize it
• B) decompose it
• C) minimize its decomposition
• D) reduce it to water and oxygen

Which of the following statements explains why tetraoxosulphate (IV) acid is reqarded as a strong acid?

• A. Tetraoxosulphate (IV) acid is dibasic
• B. the acid is concentrated
• C. the acid is complately ionized in aqueous solution
• D. tetraxosulphate (IV) ions are very reactive