Correct Answer: A. copper (l) oxide

Correct Answer: B. margarine

Explanation

(a)(i) Contract process

(ii) Vanadium (v) oxide (V\(_2\)O\(_5\))

(iii) 2SO\(_{2(g)}\) + O\(_{2(g)}\) \(\rightleftharpoons\) 2SO\(_{3(g)}\)

SO\(_{3(g)}\) + H\(_2\)SO\(_4\)\(_{(/)}\) \(\to\) H\(_2\)S\(_2\)O\(_7\)

H\(_2\)S\(_2\)O\(_7\)\(_{(/)}\) + H\(_2\))\(_{(/)}\) \(\to\) 2H\(_2\)SO\(_{4(aq)}\)

(b)(i) Dehydration is the removeal of the element of water from a compound with change in the chemical composition of the compcu while drying is the removal of associated water from a substance without affecting it chemical composition.

(ii) Concentrated H\(_2\)SO\(_4\) reacts with ammonia to form ammonium tetraoxosulphate (VI)

(iii) CaO or silica gel.

(c)(i) I. lead chloride (PbCl\(_2\))

II. K\(_2\)CO\(_3\) or Na\(_2\)CO\(_3\)

III. ZnO or Al\(_2\)O\(_3\)

(ii) I - Reaction of an acid with base (neutralization reaction)

- Reactiction of an acid with a metal

- Reaction of an acid with trioxocarbonate (IV)

- Double decomposition

- Direct combination of its constituent element

- A metal with halogens

(iii) - Evaporation

- Crystallization

(d)(i) Gay lussac's Law of coming volumes states that when gases react, they do so in volumes which are in simple ratio to one another and to the volumes of the products if gaseous, provided that the temperature and pressure remains constant.

(ii) C\(_2\)H\(_{4(g)}\) + 3O\(_{2(g)}\) \(\to\) 2H\(_2\)O + 2Cl\(_{2(g)}\)

1 cm\(^3\) of ethene requires 3cm\(^3\) of oxygen

12.5cm\(^3\) of ethene will require 3 x 12.5cm\(^3\) of oxygen = 37.5cm\(^3\)

Correct Answer: C. Ionic radius

Explanation

(a)(i) A saturated solution is one that will dissolve no more of the solute at a particular temperatuie in the presence of excess solute.

(ii) Solubility is the,maximum amount of solute (number of moles/mass) that dissolves in 1dm\(^3\) of solvent at a particular temperature.

(b) Mass of saturated solution = 17.85 — 7.16 = 10.69

Mass of dry salt = 9.30 — 7.16 = 2.14

Volume of solution = 10.69cm\(^3\)

Since volume of solution = \(\frac{mass}{density}\)

and density = 1.0g/dm\(^3\)

(i) Solubility in g/dm\(^3\)

10.69cm\(^3\) of solution Y contains 2.14g of salt Y

1cm\(^3\) of solution Y contains \(\frac{2.14 }{10.69}\)

1000cm\(^3\) = \(\frac{2.14 \times 1000}{10.69}\) = 200.19g/dm\(^3\)

(ii) Solubility in mol/dm\(^3\) = \(\frac{\text{solubility in g/dm}^3}{\text{molar mass of salt Y}}\)

= \(\frac{200.19}{100}\)

= 2.00 mol/dm\(^3\)

(c) NaCI — Ionic bond of electrovalent bond

CO\(_{2}\) — van der Waals forces

SiO — Covalent bond Al\(_{(s)}\) — Metallic bond.

(d)(i) Reactivity is due to loss of electrons, i.e the ease of electron loss, hence ionization energy decreases down the group.

(ii) Mg has more valence electrons contributing to the stronger binding energy compared to Na.

(iii) Potassium loses electron more readily than sodium, has lower ionization energy than sodium.

(e)(i) Isotopes are atoms of the same element with the same atomic number but different mass number.

(ii) Li = \(\frac{2 \times 6}{27}\) + \(\frac{25 \times 7}{27}\)

= 6.925

Correct Answer: A. Their outermost shells are fully filled

Explanation

(a)(i) Homologous series is a series are family of organic compounds with a general molecular formula, similarity in property and differing from successive member by CH\(_2\) of 14 a.m.u.

(ii) Alkanes, alkenes, cycloalkar les and aromatics.

(iii) Alkane — methane; ethane, etc.

Alkene — ethene, propene, butene, etc

Cycloalkanes — cyclohexane,

cyclopropane Aromatic — benzene.

(iv) Gas Petroleum ether Gasoline (petrol) Gas oil/diesel oil Lubricating oil Biturhen Kerosine.

(v) Because of a steady change (increase or decrease) in molecular mass of tho constituents.

(b)(i)

I. C\(_2\)H\(_5\)OH\(_{(l)}\) + H\(_2\)SO\(_4\)\(_{(l)}\) \(\to\) C\(_2\)H\(_5\)HSO\(_4\)\(_{(l)}\) + H\(_2\)O\(_{(l)}\)

II. C\(_2\)H\(_5\)HSO\(_4\)\(_{(l)}\) \(\to\) C\(_2\)H\(_4\)\(_{(g)}\) + H\(_2\)SO\(_4\)\(_{(l)}\)

(ii) I. C\(_2\)H\(_5\)OH\(_{(l)}\) + H\(_2\)SO\(_4\)\(_{(l)}\) ---> C\(_2\)H\(_5\)HSO\(_4\)\(_{(l)}\) + H\(_2\)O\(_{(l)}\)

II. C\(_2\)H\(_5\)HSO\(_4\)\(_{(l)}\) \(\to\) C\(_2\)H\(_5\)OC\(_2\)H\(_5\)\(_{(l)}\) + H\(_2\)SO\(_4\)

(c)(i)

(I) C H O

52.0 13.3 34.7

12 1 16

4.33 13.3 2.17

2.17 2.17 2.17

1 6 1

Emperica formula = C\(_2\)H\(_6\)O

(II) (C\(_2\)H\(_6\)O)\(_n\) = 46

(12 x 2 + 6 x 1 + 16)\(_n\) = 46

46\(_n\) = 46

n = \(\frac{46}{46}\) = 1

molecular formula = C\(_2\)H\(_6\)O

(ii)

Correct Answer: C. C₆H₁₂

Correct Answer: D. nitrogen and noble gases

Explanation

(a)(i) Oxidation is the process of electron loss. Reduction is the process of electron gain

(b)(i) POCI\(_3\)

O.N of P + O.N of oxygen + (O.N of CI) x 3 = 0

P + —2 + —1 x 3 = 0

—P — 2 — 3 = 0

P = — 5

(ii) I. NaNO\(_3\) is neutral because it is a salt of a strong acid and a strong base, its ions do not undergo hydrolysis.

II. NH\(_4\)CI is acidic because it is a salt of a strong acid and a weak base. The NH\(^+_4\) undergoes hydrolysis.

III. Na\(_{4}\)CO\(_3\) is basic because it is a salt of weak acid and ntrong base. The CO\(^{2-}_3\) undergoes hydrolysis.

(c)(i) Hydrogen chloride gas

(ii) downward delivery or upward displacement of air.

(iii) The gas is denser than air

(iv) drying the gas.

(v) Physical properties

— denser than air — very soluble in water — colourless gas — fumes in moist air

Chemical Properties

— gives cloud or white fumes in contact with ammonia vapour

(vi) Pass the gas into AgNO\(_{3(aq)}\) a white precipitate of AgCl is formed wihich is soluble in aqueous ammonia but insoluble in HNO\(_3\)

(d) Mass of water = 4.30 — 2.12 = 2.18g

Mass of Na\(_2\)SO\(_4\) = 23 x 2 + 32 + 16 x 4 = 142

Molar mass of H\(_2\)O = 2 + 16 = 18

2.12g of anhydrous salt contain 2.18g of water

142g of anhydrous salt contain \(\frac{2.18 \times 142}{ 2.12}\)

= 146.018

X(H\(_2\)O) = 146

18x = 146

x = \(\frac{146}{18}\)

= 8