Fair Test:
In order for me to make my experiment a fair test, I must ensure that a number of things are correct:
I must ensure that the exact and equal amount of Sodium Thiosulphate and Hydrochloric Acid are put in the flasks at every experiment.
I must ensure that my stop clock is started as soon as the Hydrochloric Acid is added to the Sodium Thiosulphate.
I must ensure that my tubes and beakers were thoroughly washed out before re-using them as there should not be any other chemicals in the beakers before hand influencing the outcome of the material.
I must ensure that I use the same concentration for each of my experiments.
Equipment Used:
For my experiment, I used a number of equipment which helped me.
- Sodium Thiosulphate (50cl each experiment)
- Hydrochloric Acid (5cl each experiment)
- Bunsen Burner
- Tripod
- Bench Mat
- Flask Net
- Conical Flask
- Thermometer
- Goggles
- Splints
- Stop clock
- Measuring Cylinder
- “X” Card
Methods:
Before each of my experiments I prepared my conical flask of 50cl of Thiosulphate Solution and 5cl of Hydrogen Acid in a measuring cylinder.
I ensured my stop clock was set at 0seconds for all experiments and each piece of equipment which had been in contact with any of the solutions was washed out.
For room temperature, I simply poured the Hydrochloric Acid into the Thiosulphate solution which was already on the X Card. I immediately began the stop clock and waited until I could no longer see the “X” at the bottom of the beaker. Once the “X” had disappeared completely, I stopped the stop clock and recorded my results. I then washed out all the equipment I used thoroughly ready to use it again for the next experiment. This is shown in a diagram below.
For 0*C, the same method was used as room temperature, except once I put the Thiosulphate Solution into the beaker, I put it in a bucket of ice with a thermometer in it and waited until the temperature reached 0*C. I then brought the beaker back onto the “X” Card and added the Hydrochloric Acid. Again, I timed how long it took for the “X” to disappear. This is shown in the diagram below.
For the heated experiments, I prepared the Hydrochloric Acid in the beaker and put in on a Bunsen Burner to heat. I had a thermometer in the beaker and once the Hydrochloric Acid had reached my desired temperature, I took it off put it on the “X” Card and added the Thiosulphate solution. I then watched and timed the reaction until the “X” disappeared. I repeated this method for all of my heated experiments. This is shown in the diagram below.
Results:
Each of my experiments was taken twice. Below are the results of the first and second attempts of each the experiments. It also shows the range of temperatures I used.
My results clearly show that as the temperature of the solution raised, the length of time the reaction between Hydrochloric Acid and Thiosulphate Solution happened decreased.
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The next two pages show the graphs I drew from my results. The clear slope in both of the graphs show the rate of reaction increasing as the temperature increases.
Evaluation:
I think I completed this coursework well and effectively, I gained the results I was hoping to achieve and took all the safety precautions which were necessary.
However, I was unorganised at some points of the experiment such as when the Thiosulphate Solution came off the Bunsen Burner at one stage I realised I had not prepared my Hydrochloric Acid. This could have allowed the solution to slightly cool, making my experiment not as reliable as they should have been.
For my coursework, in order to make my results more accurate, I could have repeated my experiments more than twice to ensure that my rule of when temperature increases rate of reaction is quicker. I also could have used different equipments in order to make my results more accurate. By using a more enhanced form of technology, my results could have been better scientifically proven.
Conclusion:
In conclusion, from doing the practical experiment, I have realised that my hypothesis is correct. As we increase the temperature of the solution, we increase the rate of reaction. When we raise the temperature of the solution, the heat causes the particles of solution gain more energy. This causes them to move around more vigorously, colliding with each other. The more heat that is giving these particles energy, the quicker the reaction will be as the collisions will be greater.
This is shown by the obvious pattern in my results.
Overall, I am very pleased with my results.
