Question 1
The electron arrangement of ions X3+ and Y2- are 2.8 and 2.8.8 respectively.
a) Write the electron arrangement of elements X and Y.
X -
Y -
b) Write the formula of the compound that would be formed between element X and Y.
Answer
a) X - 2.8.3
Y - 2.6
b) X2Y3
Y - 2.6
b) X2Y3
Question 2
2. Study the equation below;
a) By use of arrows, indicate oxidation and reduction reactions in the equation.
b) Name the reducing agent in the above reaction.
Answer
a) 
b) Reducing agent – Mg
b) Reducing agent – Mg
Question 3
Distinguish between the terms deliquescent and efflorescent salts.
Answer
Deliquescent salts absorbs water from the atmosphere and form a solution while efflorescent salt loose water of crystallization to the atmosphere.
Question 4
The table below shows PH value of different solutions.
| Solution | A | B | C | D |
|---|---|---|---|---|
| PH | 14 | 7 | 2 | 11 |
a) Which solution is likely to be sugar solution?
b) Two of the solutions were found to react with both aluminium oxide and zinc oxide. Identify the two giving reasons.
Answer
a) B
b) A and C
b) A and C
Question 5
Identify the methods that are most appropriate to obtain.
a) Oil from coconut
b) Diesel from crude oil
c) Sugar crystals from sugar solution
Answer
a) Solvent extraction
b) Fractional distillation
c) Crystallisation / Evaporation
b) Fractional distillation
c) Crystallisation / Evaporation