Fair Test
To make all experiments a fair test we used the same amount of Hydrochloric acid through out the experiment (5cm3). We also used the same piece of paper with a drawn cross. We also used the same stopwatch through out the experiments.
Hypothesis
For this experiment I predict that if there is an increase in temperature, there will be an increase in the rate of reaction. Inn other words the hotter the temperature the faster the reaction. On the other hand if the temperature consists of a low degree then the reaction will take time.
I predict that, if the concentration of Sodium Thiosulphate is constant and the temperature is high and the concentration of hydrochloric acid is kept constant the speed of the reaction will be twice as fast. The more often they collide, the more chance they have of reacting. Temperature will alter the rate of reaction by supplying the reactant particles with more energy, the more energy the reactants have the faster they move around increasing there chance of bumping into one another and having a successful collision. Also the more energy they get from the heat the more particles have enough energy to react, this is known as activation energy. The greater the temperature the faster the rate of a reaction, the rate doubles every 10c.
Collision Theory
- For a reaction to occur, molecules must collide with each other.
- Molecules must possess at least a certain minimum energy necessary to break the bonds.
- Molecules must have the proper orientations.
- Increased temperature of reactants results in greater numbers of collisions per unit time.
Method
- Draw a pencil cross on a piece of paper and place it in a transparent sleeve
- Rinse the conical flask with distilled water
- Rinse and dry both beakers
- Put a certain amount of water and sodium Thiosulphate into a conical flask
- Place this into the thermostatic bath for the required temperature
- Leave for 5-10 Mins until reached certain temperature
- Take out the conical flask from the thermostatic bath, take to the desk and at once put hydrochloric acid in and start stop watch, take the start temperature and wait until mixture goes cloudy and the pencil cross is unable to be seen, stop watch immediately
- Record temperature and time
- Repeat experiment at differentTemperatures.
Diagram
OBSERVER
Results
From the results in the table and the graph we can see that the cross disappears soonest when the solution is hottest and the hotter they are the more often they collide, giving a faster reaction.
Conclusion
From this experiment I have reached to a conclusion that a solution with a higher temperature will give a faster reaction. If there is more collision every minute, there will be more reactions every minute, which means there will be a faster reaction. Therefore a higher temperature and more concentration mean a faster reaction. As can be seen from the results above.
Evaluation
By doing the experiments again would be an improvement to this investigation and by gaining accurate results. Some of my results were anomalous to others although there was a pattern in my results as the line in the graph steeples soonest when the solution is hottest. I could also improve the method in this investigation. There may be aspects of original investigations that I could investigate. The most difficult part of the procedure was getting all the solution, dilute as possible and recording the temperature accurately. My graph was fairly accurate although there was one anomalous result; this was due to the lack of attention paid to the solutions. If this test was repeated then my result would be correct but due to the shortage of time it was impossible. I could extend the enquiry by doing the experiment again and by obtaining more accurate and reliable results.
Safety and Hazards
To make this experiment safe we wore safety glasses and lab coats to ensure our cloths were not damaged and glasses to protect our hands as some may have allergies to chemical products.
