In scientific study, the tentative explanation for the observed chemical phenomenon can be proved by:

1. Data analysis
2. Experimentation
3. Hypothesis
4. Observation

A certain liquid dissolves copper (Il) sulphate to form a blue solution. This liquid is likely to be:

1. Hydrochloric acid
2. Liquid oxygen
3. Nitric acid
4. Water

When a chemist studies a substance he/she is interested in its:

1. Force of attraction
2. Properties
3. Shape
4. Smell

The boiling point of pure water at sea level is 100⁰C and that of ethanol is 78⁰C. The mixture of ethanol and water can be separated by:

1. Filtration process
2. Fractional distillation process
3. Layer separation process
4. Sublimation process

The boiling point of pure water at sea level is 100⁰C and that of ethanol is 78⁰C. The mixture of ethanol and water can be separated by:

1. Filtration process
2. Fractional distillation process
3. Layer separation process
4. Sublimation process

Which group among the following elements are metals?

1. Calcium, magnesium and sodium
2. Calcium, hydrogen and nitrogen
3. Calcium, carbon and magnesium
4. Oxygen, potassium and sodium

An electrovalent bond is formed by:

1. Arrangement of electrons
2. Sharing of electrons
3. Transfer of electrons
4. Vibrations of electrons

Petrol is an example of:

1. corrosive substance
2. flammable substance
3. irritating substance
4. toxic substance

The electronic configuration of silicon is:

1. 2:7:3
2. 2:8:2
3. 2:8:3
4. 2:8:4

The most abundant element on the earth is:

1. carbon
2. iron
3. nitrogen
4. oxygen