This experiment is to investigate the rate of reaction between Sodium Thiosulphate and Hydrochloric acid. The equation for this reaction is:.
Na2S2O3 (aq) + 2HCl (aq) 2NaCl (aq) + S (s) + H2O (L) + SO2 (g).
Sodium + Hydrochloric Sodium + Sulphur + Water + Sulphur.
Thiosulphate Acid Chloride Oxide.
Prediction.
I predict that the higher the concentration of acid, the quicker the reaction. The higher the concentration, the more particles in the acid, which makes more of a chance that the particles will collide - so more chance of a reaction taking place.
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Apparatus.
• 1 pair of safety goggles.
• paper.
• 1 felt tip pen.
• Conical flask.
• 25cm3 sodium Thiosulphate.
• 10cm3 hydrochloric acid - 0 molar.
- 0.5 molar.
- 1 molar.
- 1.5 molar.
- 2 molar.
• 1 stop clock.
• 2 measuring cylinders - 100cm3.
Method.
• Put on safety goggles. .
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• Take a piece of paper and draw a cross in the centre of it using the felt tip pen. .
• Measure out 25cm3 Sodium Thiosulphate using one of the measuring cylinders and pour it into the conical flask. .
• Place the paper under the conical flask. .
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• Measure out 10cm3 of the 0 molar concentration of Hydrochloric acid, using the other measuring cylinder. .
• Pour the acid into the conical flask and immediately start the stop clock. .
• Watch the reaction. When you cannot see the cross anymore, stop the clock.
• Repeat this again using 0.5, 1, 1.5 and 2 molar concentration of hydrochloric acid.
Fair test points.
To make this a fair test, make sure that:.
• your measurements are accurate.
• you use the same cross for each experiment.
• repeat the experiment 3 times.
