Fair Test
I intend to conduct an experiment that will be as fair as possible. Means of doing this will include.
- Keeping the temperature of both chemicals the same throughout the experiment.
- We will not mix any of the experiments. Only pour the two chemicals in together.
- Make sure that the lighting in the room is the same all through the experiment.
- Ensure that the person, me, checking the flask until it turns completely white, stays as that person. If someone else did it then that persons judgment may be different or may have different eye site.
Hypothesis
I anticipate that the rate of reaction will be directly linked to the concentration of the chemicals. Therefore if there is a higher concentration then the reaction will have a shorter duration to react. This analysis has been drawn up from the particle collision theory. With a brief explanation, collision theory is where the molecules in a given area are either moving faster, caused by heat, or a higher concentration of that particular molecule. When one of these two or both elements occur then the molecules are more likely to hit each other, but also they will hit harder. If the molecules hit harder they have a better chance of reacting.
Equipment
- 6 X Beakers
- 2 X Pippets
- 2 X Goggles
- Paper with black cross
- Hydrochloric Acid
- Sodium Thiosulphate
- 1 X Flask
Method
- Measure 5 different quantities of Sodium Thiosulphate. These are 50 cm3. 40cm3 and 10 cm3 of water. 30 cm3 and 20 cm3 of water. 20 cm3 and 30 cm3 of water. 10 cm3 and 40 cm3 of water. Prepare these into beakers ready for later.
- Get the flask and place the paper with the cross on it, and place it under the flask.
- Measure 10cm3 of Hydrochloric acid. (This measurement will be the same every time)
- Wash out the flask after each experiment.
- Follow the instructions from method 1 and use the pre made measurements and mix with the acid in the flask.
- Time how long it takes for the solution to turn white.
- Write down the records
Conclusion
Our experiment proved successful and showed what we expected. As you can see from the table and graph, it shows that as the concentration is higher then the reaction time will be lower. This proves the collision theory concept. And further increases our base knowledge of concentration and rates of reaction.
Clearly here you can see the less sodium thiosulphate there is and the more water content there is in the solution then the time in which it takes to react increases considerably.
Evaluate
Our investigation was successful and proved a good point. Our experiment could have been conducted more accurately though by using lighting equipment to show when the solutions density fell to a point that only a certain bit of light could be penetrated. This would make the experiment more fair and much more accurate. Our graph displays a gradient that has been evident in other pupil’s experiments.
Extension
Other ways of possibly extending research on collision theory would to do different types of tests. This could be on how temperature affects rate of reaction. However due to time constraints in lesson time we are unable to conduct any further experiments.
