Title : Solution and SolubilityAim : To study the effect of different volumes of water on the rate of dissolving salt.Hyphotesis : The higher the volume of water, the shorter time taken to dissolve the salt.Variables : a) Manipulated : Volume of water

b) Responding : Time taken to dissolve the salt c) Fixed/Constant : Mass of salt / temperature of water / rate of

stirring / type of salt.

Apparatus and Materials :Beam balance, stopwatch, 3 beakers (250 ml), fine salt, glass rod, measuring cylinder.

Procedure :1. Beaker A is filled with 50 ml of water, beaker B is filled with 100 ml of water and beaker C is filled

with 200 ml of water.2. Water is at room temperature.3. 10 g of salt is weighed with a beam balance and added to each beaker.4. The solution in each beaker is stirred at the same rate until all the salt dissolved completely.5. Time taken for salt to dissolve is recorded for each beaker.

Observation:Table of results :

Beaker Volume of water(ml)

Time taken to dissolve salt (second)

A 50 120B 100 60C 200 45

Discussion and Analysis:

i) Which volume of water dissolves the salt:a. the fastest200 ml of water in beaker C dissolves fastest because it has the largest volume of water.

b. the slowest50 ml of the water in beaker A dissolves salt the slowest because it has the lowest volume of water.

ii) State the relationship between the volume of water and the time taken to dissolve salt in water.

The larger the volume of water, the less time taken to dissolve salt.

iii) Based on the table of results, define operationally the ‘ rate of dissolving salt’.Rate of dissolving salt is the time taken to dissolve all (10g) salt completely in water.

iv) Based on the table of results, what will happen to the time taken to dissolve salt when more than 200 ml of water is used?If more than 200 ml of water is used, the time taken to dissolve salt will be less than 45 seconds.

v) Arrange the beaker according to the rate of solubility of salt in ascending order ?C, B, A

Conclusion:

Time taken to dissolve salt depends on the volume of water.

SCIENCE FORM 2

STUDENT MANUAL

Theme : Matter in Nature

Learning Area :Water and Solution

Learning Objective : Solution and Solubility

Assignment Sample : Task Report

Element Assessed : E1(C7,C8, C9, C10 & C11)

Instruction:

You are required to device and carry out a scientific experiment to determine the rate of

dissolving solute. Following that, you are required to write a task report on that activity.

The following guidelines will help you prepare an elaborate and complete task report.

1. Title : Solution And Solubility

2. Aim : To study the relationship between volume of water and the rate of dissolving salt in water

3. Hypothesis : (C11 a,b)

4. Variables : (C 10 a,b)

i. Manipulated :

ii. Responding :

iii. Fixed / Constant :

5. Apparatus and materials.

6. Procedure (passive form). (C10 c)

7. Results / Observation (presents qualitative data in table). ( C7a & C8 a,b )

8. Discussion. (based on the results, answer the question given)

i. Which volume of water dissolves the salt.

a. the fastest. (C7 c)

b. the slowest and explain why? (C8 d)

ii. State the relationship between the volume of water and the time taken to dissolve salt in

water. (C7d & C11 c)

iii. Based on table of results, define operationally the “rate of dissolving salt”. (C9 a,b)

iv. Based on table of results, what will happen to the time taken to dissolve salt when more

than 200 ml of water is used? (C7 d)

v. Arrange the beaker according to the rate of solubility of salt in ascending order ? (C7 b)

9. Conclusion. (C8 c)

10. All report should be submitted to your science teacher 3 days after the investigation.