Correct Answer: A. handling of any change(s) without having to rewrite the entire program.

Correct Answer: D. the parable of the Weeds Among the Wheat

Explanation

(a) Define esterification: Esterification is the reaction between an alkanol and alkanoic/organic acid to produce an alkanoate/ester and water in the presence of mineral acid.

(b) Properties ottitastic: —Good insulators to heat and electricity. —Can be recycled. —Are non-biodegradable. —Are durable.— can be tailor-made (to suit particular purpose). —Are resistant to corrosion/chemicals. —Can be remoulded.

(c) Components of duralumin: —Aluminium, —Magnesium. —Copper. —Manganese.

(d)(i) What is meant by raw material: Raw material is a starting material used in producing or manufacturing a substance/product.

(ii) What is meant by primary product: This is the main product of the industry/an intermediate product that can be still converted to other usable product.

(e) Charles' law: It states that the volume of a given mass of gas is directly proportional to its absolute temperature/ temperature in Kelvin if the pressure is constant.

(f) Protective equipment in the laboratory: —Safety goggle. —Hand gloves. —Laboratory coat/apron. —Boots or safety boot. —Nose mask/shield. —Fume cupboard. --Respirator/ gas mask. —Fire extinguisher.

(g) Uses of Ammonia: —As a refrigerant. —For electing aluminium. —As agent for manufacturing of fertilizer. —As solvent for removal of grease and oil stains. —For softening of temporarily hard water. —Use in making/manufacturing ammonium salt. —For treating insect bite. —As agent for manufacturing of HNO\(_3\). —As a precipitating agent for qualitative analysis.

(h)(i) Process by which lighter hydrocarbons are obtained from heavier ones: —Cracking.

(ii) Products:formed from the reaction between ethanol and sodium metal: —Sodium ethoxide + Hydrogen gas.

(iii) Oxidation number of sulphur in H\(_2\)SO\(_4\)

H\(_2\)SO\(_4\) = 2 x 1 + 5 + 4(-2) — 2 = 0

= 2 + 5 — 8 = 0

2 + 5 = 8

5 = 8 — 2 = 6

5 = 6

(j) IUPAC name of: (i) NaClO\(_3\) —>Soludium trioxochlorate(V).

(ii) CUSO\(_4\)SH\(_2\)O —> Copper (II) tetraoxosulphate (VI) —> -pentahydrate

Correct Answer: B) dry the gas

Correct Answer: A. RPQ

Explanation

(a)(i) \(T_{n} = ar^{n - 1}\) (terms of a G.P)

\(T_{1} + T_{2} + T_{3} = a + ar + ar^{2} = 7 ... (1)\)

\(a(ar)(ar^{2}) = 8 .... (2)\)

\((a^{3} r^{3}) = 8 \implies (ar)^{3} = 2^{3}\)

\(\therefore T_{2} = ar = 2\)

\(a + ar^{2} = 5 \implies a(1 + r^{2}) = 5\)

\(a = \frac{5}{1 + r^{2}}\)

\((\frac{5}{1 + r^{2}})(\frac{5r^{2}}{1 + r^{2}}) = 4 = 2^{2}\)

\(\frac{25r^{2}}{(1 + r^{2})^{2}} = 2^{2}\)

Taking square root of both sides, we have

\(\frac{5r}{1 + r^{2}} = 2 \implies 5r = 2 + 2r^{2}\)

\(2r^{2} - 5r + 2 = 0 \implies 2r^{2} - 4r - r + 2 = 0\)

\(2r(r - 2) - 1(r - 2) = 0 \implies r = \frac{1}{2} ; r = 2\)

Since it is a decreasing sequence, the common ratio \(r = \frac{1}{2}\).

(ii) \(T_{2} = 2 = ar\)

\(\frac{a}{2} = 2 \implies a = 4\)

\(T_{3} = ar^{2} = 4(\frac{1}{2})^{2}\)

= \(4(\frac{1}{4}) = 1\)

\(\therefore \text{The first 3 terms of the sequence are } 4, 2, 1.\)

(b) \(\int_{1} ^{5} (x + \frac{2}{x^{2}}) \mathrm {d} x\)

\(Height (h) = 1 ; y_{1} = 3.0 ; y_{5} = 5.08\)

\(y_{2} = 2.5 ; y_{3} = 3.222 ; y_{4} = 4.125\)

\(y_{1} + y_{5} = 3.0 + 5.08 = 8.08\)

\(y_{2} + y_{3} + y_{4} = 2.5 + 3.222 + 4.125 = 9.847\)

\(2(y_{2} + y_{3} + y_{4}) = 2(9.847) = 19.694\)

\(Area = \frac{1}{2} \times 1[8.08 + 19.694]\)

= \(\frac{1}{2} [27.774]\)

= \(13.887 \approxeq 13.89\) (to 2 d.p.)

Correct Answer: A. Lagos to Kano

Correct Answer: D. Saponification

Explanation

(a)(i) Benefit of agriculture to the economy of West African countries:

provision of food for humans

Supply of raw materials for industries

provision of income to farmers

provision of feeds for livestock

provision of foreign exchange

promotion of tourism through conservation of wildlife and flora

- Provision materials for shelter/housing

- Provision of employment

- Creation of market for farm inputs, tools, equipment

-Promotion of rural development

(b) Functions of agro-service centres

- Repair/maintain agricultural tools, machines and equipment

- Supply farmers with seeds and fertilizers

- Provide technical/extension services in agriculture to needy farmers

- Supply of spare parts of agricultural tools, machines and equipment

- Supply of vaccines/drugs to farmers for disease control

- Supply farmers with agrochemicals for weed and pest control

- Provide inputs at subsidized rates to farmers

(c)Routine tractor maintenance practices:

- Check engine oil and top if necessary

- Check water level and top if necessary

- Grease kingpins, three - point linkage and steering joints/moving parts

- Check and clean air cleaner if necessary

- Check and replenish battery electrolyte if necessary

- Change engine oil periodically

- Check and adjust fan belt if necessary

- Change fuel filters periodically

- Service fuel injector periodically

- Check radiator water level and top if necessary

- Clean the tractor after use

- Park the tractor in the shed when not in use

- Change oil filter periodically

(d) Functions of parts of the tractor :

(i) Three – point linkage

- Point of attachment for coupled implements

- Allows the raising and lowering of implements

- Regulates the depth and variation of thrust/depth of plough according to

soil conditions

- Helps to maintain a constant draught/force

- Helps in the transfer of weight to the rear wheels of the tractor

(ii) Hydraulic lever

- Controls the raising and lowering of implements

- Controls lowering and holding of an implement to a pre-determined

position

- Operates external hydraulic equipment, such as tipping trailer and

loaders

- Used to control above-the-ground implements such as mowers.

Correct Answer: A. 48