What effect does temperature have on the rate of a reaction?

Apparatus:

• Sodium thiosulphate solution
•  Hydrochloric acid
• 250cm conical flask
•  -5 C -110 C thermometer
•  10cm /50cm measuring cylinder
•  Stop clock
•  Paper with a cross on it.

Prediction

As I explained earlier, the rate of a chemical reaction is the speed at which it takes place. Temperature is a major factor in this as increasing or decreasing the temperature changes the movement of particles in a substance therefore changing the rate of reaction. When a reaction mixture is heated up, each particle in it acquires more energy and collides more with other particles.  Thus, from my prior knowledge and research, I can make the prediction that if you increase the temperature of a particular reaction, you increase the speed at which it takes place. This is simply because the particles carry more energy and collide more often where these collisions contain enough energy to break the energy barrier:
 When the temperature is raised, particles, when moving faster, collide with greater power. The reaction therefore becomes faster. Collisions between particles are useless unless they break the energy barrier and this is exactly what increasing the temperature will allow them to do.

Plan

1. Collect all the equipment and set up as shown in the diagram.
2. Take the two solutions in different test tubes and heat them to the required temperature in the water-bath. NB: The first temperature is 30°c.
3. Put the Sodium thiosulphate into the conical flask. As soon as you add the hydrochloric acid start to time. Keep timing until the cross has disappeared.
4. Heat the two chemicals 10°c higher and repeat the experiment until a temperature of 70°c has been reached.
5. Repeat the experiment 3 times and take an average.

Safety

• Wear goggles all the way through this practical.
• Do not let hydrochloric acid or thiosulphate come into contact with skin. If it does, wash off immediately.
• Always be careful when near the water bath.
• Follow lab safety rules at all times.

Fair test

To ensure a fair test I will:

• Do the experiment in the same area to keep the ambient temperature roughly the same.
• I will repeat each experiment three times. I will do this to enable me to take an average which will be much more accurate then just doing the experiment.
• I will use a burette to measure out the quantities using a burette. This will mean that we only have an error margin of +/- 0.1ml per measurement taken 12x0.1/10x100= 12% error due to burette measurement.
• If my initial results are unsatisfactory I will ask to see another groups results, I will add these to my results and take an average to ensure more accurate results.
• I will measure the volume of acid and thiosulphate in mls. I will measure the temperature in°C. I will measure time in seconds.
• I will not do data manipulation to my results only if some data is anomalous and there is a definite pattern to the results that are accurate.

Results table