1.2.3 - Laboratory Activity : The Effect of Temperature on the Rate of Reaction

Laboratory Activity 1.2.3: The Effect of Temperature on the Rate of Reaction

Aim: To understand the effect of temperature on the rate of reaction.
Problem statement: How temperature affects the rate of reaction of reaction.
Hypothesis: The higher the temperature, the faster is the rate of reaction.
Variable:

	»	Fixed variable : Concentration and volume of the solution
	»	Manipulated variable : Temperature
	»	Responding variable : Rate of reaction

Material: » Sodium thiosulphate 0.1mol dm-3 » Sulphuric acid 1.0mol dm-3

Apparatus: » Conical flask » Thermometer » Measuring cylinder » Stopwatch » Wire gauze » Bunsen burner » Filter paper » Tripod

Procedure:

	►
	►	1. 50cm3 of sodium thiosulphate 0.1mol dm-3 is measured with a measuring cylinder and poured it into a conical flask. 2. The temperature of the sodium thiosulphate solution is recorded. 3. A cross 'X' is drawn in the middle of the filter paper. A conical flask containing the sodium thiosulphate solution is placed on top of the marked filter paper. 4. 5cm3 sulphuric acid 1.0mol dm-3 is measured by measuring cylinder. 5. The sulphuric acid is added quickly into conical flask containing sodium thiosulphate solution. The stopwatch is started at the same time. 6. The conical flask solution is swirled slowly. 7. The stopwatch is stopped when the cross can no longer be seen from the above. 8. The time taken for cross 'X' disappear are recorded. 9. The experiment is repeated by using different temperature.

Results:

►

Volume of sodium thiosulphate (cm3) Volume of sulphuric acid (cm3) Temperature of solution (°C) Time t (s) $\frac{1}{\mathrm{time}}$ (s-1) 50 5 28 33 0.030 50 5 35 24 0.042 50 5 40 19 0.053 50 5 45 16 0.063 50 5 50 14 0.071

Discussion:

	►	Sodium thiosulphate solution reacts with hydrochloric acid to form sulphur precipitate slowly as shown in the following equation: ○ Na2S2O3(aq) + H4SO4(aq) → Na2SO4(aq) + H2O(l) + SO2(g) + S(s) ○ The time taken for the precipitation of the sulphur is used to to determine the rate of reaction.
	►	Graph of temperature against time. ○ Based on the graph of temperature against time, we can be observed that when the temperature of sodium thiosulphate increases, the time it takes for cross 'X' to disappear decrease. ○ This means that when the sodium thiosulphate having higher temperature, the rate of reaction increases as well.
	►	Graph of temperature against $\frac{1}{\mathrm{time}}$ ○ The graph of temperature against $\frac{1}{\mathrm{time}}$ is a straight line. This means that the temperature of sodium thiosulphate directly proportional to $\frac{1}{\mathrm{time}}$. ○ The higher the temperature of the reactants, the higher is the rate of reaction. In theory, when the temperature increases by 10°C, the rate of reaction will be doubled.

Conclusion:

►

The higher the temperature, the faster is the rate of reaction.

⇲ For exercise(objective and subjective), download for free on Android OS.