Page 57 - Chemistry_Form_2

Chemistry
for Secondary Schools

(e) They are generally insoluble in non-polar solvents such as carbon
tetrachloride and hexane. Non-polar solvents contain bonds between atoms
with similar electronegativities.
(f) They are typically hard but brittle.
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(g) They have high densities.

Activity 3.1

Aim: To investigate the electrovalent bonding in substances

Requirements: Table salt (sodium chloride), cooking oil, slaked lime, baking
powder, sugar, three glass beakers, distilled water, a tablespoon,
an electrical conductivity meter (or a small LED bulb with wires
and a battery), and three stirring rods

Procedure

1. Fill a glass beaker with distilled water and add 2 tablespoons of table salt
(sodium chloride). Stir with the stirring rod until the salt dissolves completely.

2. Attach the electrical conductivity meter (or set up the bulb circuit) to
the solution. Observe whether the bulb lights up or the tester indicates
conductivity.

3. Repeat Steps 1 and 2 for the baking powder, cooking oil, slaked lime, and
sugar. Use a separate stirring rod for each substance.
4. Record your observations as shown in Table 3.2.

Table 3.2: Experimental results
S/N Substance Solubility Conduct electricity
Yes No
1 Table salt

2 Baking powder

3 Sugar
4 Slaked lime

5 Cooking oil

50 Student’s Book Form Two

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