2023 NECO CHEMISTRY ESSAY ANSWERS

Here is the neco Chemistry questions and answers

(1ai)
(CHOOSE ANY BEST 3)
(i) Sulphur is used to produce sulphur(IV)oxide for manufacturing tetraoxosulphate(VI)acid
(ii) Sulphur is used in the vulcanization of rubber.
(iii) Sulphur and some of its products are used as fungicides and insecticides for spraying crops.
(iv) Sulphur is used to manufacture the bleaching agent used in the pulp and paper industry.

(1aii)
(CHOOSE ANY BEST 2)
(i) Hydrogen Sulphide is a colorless gas with a repulsive smell like that of a rotten egg.
(ii) It is very poisonous.
(iii) It is about 1.18 times denser than air.
(iv) It burns with a pale blue flame.

(1aiii)
Coming…..

???? 2023 NECO CHEMISTRY ESSAY ANSWERS ????

(1ai)
(CHOOSE ANY BEST 3)
(i) Sulphur is used to produce sulphur(IV)oxide for manufacturing tetraoxosulphate(VI)acid
(ii) Sulphur is used in the vulcanization of rubber.
(iii) Sulphur and some of its products are used as fungicides and insecticides for spraying crops.
(iv) Sulphur is used to manufacture the bleaching agent used in the pulp and paper industry.

(1aii)
(CHOOSE ANY BEST 2)
(i) Hydrogen Sulphide is a colorless gas with a repulsive smell like that of a rotten egg.
(ii) It is very poisonous.
(iii) It is about 1.18 times denser than air.
(iv) It burns with a pale blue flame.

(1aiii)
Coming…..
(3)
(i) Classifying the alkanols:
– Butan-2-ol: secondary alkanol
– 2-methylpropanol: secondary alkanol
– 2-methylpropan-2-ol: tertiary alkanol

(ii) Two methods to prepare ethanol commercially:
– Fermentation: Ethanol can be produced by the fermentation of sugars using yeast. This is commonly used to produce alcoholic beverages and biofuels.
– Hydration of ethene: Ethanol can be produced by the hydration of ethene (ethylene) in the presence of a catalyst, such as phosphoric acid.

(iii) To calculate the relative molecular mass of Z, we need to compare the rates of effusion or diffusion of Z and hydrogen. The rate of effusion/diffusion is inversely proportional to the square root of the molar mass. Since hydrogen diffuses 6 times as fast, the molar mass of Z is 6 times larger than the molar mass of hydrogen. Therefore, the relative molecular mass of Z is 6 * 2 = 12.

(bi) The electronic configuration of oxygen using s, p, d, f notation is 1s2 2s2 2p4.

(ii) Three physical properties of oxygen:
(i) Oxygen is a colorless and odorless gas.
(ii) It is slightly soluble in water.
(iii) Oxygen supports combustion and is necessary for respiration.

(iii) Two rules for naming alkenes:
1. Alkenes must have the ending “-ene” in their name.
2. The longest continuous carbon chain containing the double bond is used as the base name, and the position of the double bond is indicated by the lowest possible number.

(iv) Equation for the oxidation reaction of ethene:
Ethene + Oxygen → Carbon Dioxide + Water
C2H4 + O2 → CO2 + H2O

(ci) Endothermic reaction: A reaction that absorbs heat (energy) from the surroundings, resulting in a decrease in temperature.

(ii) Equation for the laboratory preparation of hydrogen using dilute tetraoxosulphate(VI) acid and Zinc:
Zn + H2SO4 → ZnSO4 + H2

(iii) The type of reaction involved in (cii) is a displacement reaction, where zinc displaces hydrogen from the acid to form hydrogen gas.

(iv) Three uses of hydrogen:
(i) Hydrogen is used as a fuel for combustion engines and fuel cells.
(ii) It is used in the production of ammonia for fertilizer and other chemicals.
(iii) Hydrogen is used in the hydrogenation of oils and fats in the food industry.
(1ai)
(CHOOSE ANY BEST 3)
(i) Sulphur is used to produce sulphur(IV)oxide for manufacturing tetraoxosulphate(VI)acid
(ii) Sulphur is used in the vulcanization of rubber.
(iii) Sulphur and some of its products are used as fungicides and insecticides for spraying crops.
(iv) Sulphur is used to manufacture the bleaching agent used in the pulp and paper industry.

(1aii)
(CHOOSE ANY BEST 2)
(i) Hydrogen Sulphide is a colorless gas with a repulsive smell like that of a rotten egg.
(ii) It is very poisonous.
(iii) It is about 1.18 times denser than air.
(iv) It burns with a pale blue flame.

(1aiii)
Soaps are made from natural ingredients, typically fats or oils, and an alkali (such as sodium hydroxide or potassium hydroxide) in a process called saponification. WIHILE Detergents are synthetic (man-made) cleaning agents composed of various chemicals, including surfactants.

OR

Soaps are effective at removing dirt, grease, and oil, but they may not perform as well in hard water conditions. WHILE Detergents are generally more effective than soaps in all water conditions, including hard water, due to their ability to work with the mineral ions present.

(1aiv)
(CHOOSE ANY BEST 1)
(i) Detergents are used in various personal care products, such as shampoos, body washes, and hand soaps.
(ii) Detergents are specifically designed for cleaning dishes, cutlery, glasses, and cookware.
(iii) Detergents are used for general household cleaning tasks.

(1bi)

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