The effect of temperature on rates of reactions: S2

1. Rates of reactions
2P9: Wednesday 24th
November

2. Experiment
• Aim: To see what effect the
temperature has on the speed of a
chemical reaction.

3. Method
1. Measure 20ml of Sodium thiosulphate solution into a small
beaker using a measuring cylinder.
2. Mark a “X” on a piece of filter paper.
3. Place the beaker on the filter paper.
4. Measure 1ml of Hydrochloric acid and add it to the beaker –
START THE STOPWATCH!
5. Stop the watch when the cross disappears.
6. Wash the solution down the sink and measure out another 20ml
of Sodium thiosulphate.
7. Place the beaker in a hot water bath for about 2 minutes. Then
repeat steps 2-5

4. Results
Reaction temperature (degrees Celsius) Reaction time (seconds)
22o
C
55o
C

5. Conclusion
• The cross was obscured more quickly in
the experiment performed at the higher
temperature
• Therefore the experiment performed at
the higher temperature gave the fastest
reaction time
• This suggests that the higher the
temperature, the faster the speed of the
reaction

6. Explanation
• Increasing the temperature of a
reaction gives the particles more energy
which allows the particles to move
around more quickly
• This in turn increases the number of
collisions of particles, and therefore
increases the speed of reaction

7. Speed of reactions
The speed of a chemical reaction can be influenced by:
1.Particle size:
• Decreasing particle size (increasing surface area) 
Increases the speed of reaction
1.Concentration:
• Increasing concentration  Increases the speed of
reaction
1.Temperature:
• Increasing temperature Increases the speed of