2021 Nabteb Chemistry Questions and Answer (Objective and Theory)

2021 Nabteb Chemistry Questions and Answer (Objective and Theory)

OBJECTIVE ANSWERS

1-10

11-20

21-30

31-40

1ai)
Entropy is a measure of degree or disorder or randomness of a system unit is JK^-1 mol^-1.

1di)
_Under Electrovalent Compound_
1. They are solid at room temperature and do not vaporise easily.
2. They have high melting point and boiling point.
3. Elctrovalent Compounds readily dissolve in water and other polar solvent.
4. They do not dissolve in non – polar solvents such as benzene, ether, etc.

_Under Covalent Compound_
1. They are gases or volatile liquids because their molecules being electrically neutral are not bound by strong attractive force.
2. Covalent compounds readily dissolve in non – polar organic solvents such as benzene etc.
3. They have low melting and boiling points.
4. Covalent Compounds do not conduct electricity.

*Choose any 3 out of the 4👆🏽*

1dii)
1. High melting and boiling points.
2. Good Conductors of heat and electricity.
3. Relatively high densities.
4. Sonorous.
5. Malleable that is can be hammered into sheets.

_Choose any two👆🏽_

1diii)
1. Nature of reactant.
2. Surface area of the reactant.
3. Presence of catalyst.
4. Presence of light.
5. Temperature of the reaction mixture.

*Choose any 2👆🏽*

1ei) _loading…_

1eii) _loading…_

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2a) _loading….._

2b) _loading…._

2c) _loading…._

2d)
i) _loading…_

ii) _loading…_

iii) Gay Lussac’s law states that the volume of gas which take part in a chemical reaction bear a simple whole number ratio to another end to the volume of the products, if gaseous, when measured at constant temperature and pressure.
H2(g) + —— 2HCL(g)

2ei)
Hardness of water is due to the presence of dissolved Calcium tetraoxosulphate(VI), Magnesiumtetraoxosulphate(VI) and Calcium hydrogen trioxocarbonate(IV) in water.

2eii)
_Under Temporary Hardness👇🏿_
1. This type of hardness is caused by the presence of dissolved calcium hydrogen trioxocarbonate(IV) Can(HCO3)2.
2. It causes furring of kettles and boilers and also stalagmites and stalactites.

_Under Permanent Hardness👇🏿_
1. This type of hardness is caused by the presence of calcium or magnesium ions in the form of so lube chloride.
2. It can be removed by using chemicals.

2eiii)
1. Addition of caustic soda.
2. Distillation.
3. Addition of Washing Soda.

_Choose any 3👆🏽_

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*Number 1, 3 and other subjects loading…📌*

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