7) How will I record this information?
I am going to record the results I got of from the experiment on a table of results.
8) In what form will you present the recorded information?
I will present my results on a table and a line graph that will help me to compare my results.
9) What safety precautions must you take doing this investigation?
I will have to look at the safety precautions to protect myself so as I am working with chemicals I will need to wear safety goggles to protect my eyes against splashes.
Investigation
Reaction between Sodium Thiosulphate and Hydrochloric Acid
When sodium thiosulphate which is clear, is introduced to hydrochloric acid which is also clear, they react and the outcome is the creation of sulphur. This reaction turns a clear solution into a cloudy solution which is sulphur it also makes the solution opaque.
In the production of sulphur it is possible to measure the reaction. In order to due this you would first need to a piece of white paper, a conical flask, sodium thiosulphate and HC1 acid.
If I placed a piece of white paper marked with an X in the centre, then if a place a conical flask on the top of it, then added sodium thiosulphate and then added HC1 acid, the reaction takes place, this occurs to a point where the X is no longer visible, So if I recorded the amount of time it took for the X to disappear, then this is a way of measuring the reaction rate.
My aim in this investigation is to investigate the effect of altering the amount of sodium thiosulphate has on the velocity of reaction.
Chemical reactions happen all around us when we light a match, start a car. They happen when particles hit into each other this will start a chemical reaction.
My prediction is that if the sodium thiosulphate has an increased concentration the reaction will be faster so the sulphur will be made faster. This happens because the sodium thiosulphate has more particles hitting of each other this is because the solution is more concentrated therefore the reaction takes place quicker
Apparatus
Sodium Thiosulphate
HCl
Conical flask
Water
Measuring cylinders 10ml, 50ml
Stop clock
White paper with an X marked on it
Method
I marked an X in the centre of a piece of white paper with a pencil
I then placed a conical flask on top of the paper
Using a 50ml measuring cylinder 50ml of Sodium Thiosulphate is put into the flask then I add 10 ml of HCl acid to the flask
I started the stop watch and as the reaction takes place watched the X on the paper disappear.
I recorded the time it takes for the X to disappear.
I repeated the experiment two more times to make my test fair.
Then I repeated the experiment again using different amounts of sodium thiosulphate and Hydrochloric acid, the amounts are in my table
I used the results of the test to make a line graph
I will carry out the experiment in a certain way that will give me my results that I need for my investigation.
I first took a piece of white paper and marked an X in the centre of paper using a pencil, after which I placed the white piece of paper under the conical flask.
Next I put 50ml of sodium thiosulphate into the conical flask I measure the sodium thiosulphate using a 50ml measuring cylinder, then I added 10ml of hydrochloric acid which I also measured using a measuring cylinder.
I then started my stopwatch and timed the reaction until the X was no longer clear, I then recorded my results and did the experiment two more times
Table of results for my investigation
The experiment is repeated three times to ensure accuracy of method and procedure
The first line is used for the graph
Conclusions
The results in my table show that
The time for the reaction is affected by the concentration of the sodium Thiosulphate
The numbers show us that as the Sodium Thiosulphate concentration becomes less dilute the time for the reaction gets shorter.
My graph shows the same evidence, as the concentration gets weaker the time gets longer.
The evidence shows clearly, the more Sodium Thiosulphate present, the faster the reaction.
How accurate are my results
I repeated my experiment three times and because they are like the rest of my class. I think my results are accurate.
Explaining Rates
The Collision theory says that for a reaction to take place the reacting particles must:
1) collide with each other
2) the collision must have enough energy called the activation energy to be successful.
The particles in solution move around constantly. Here an acid particle is about to collide with a Sodium Thiosulphate particle.
If the collision has enough Activation Energy a reaction takes place and Sulphur begins to appear.
If the collision does not have enough energy then no reaction will take place.
If there are lots of successful collisions in a given unit of time then a lot of Sulphur is produced in that minute. The reaction can be described as fast.
If there are not as many successful collisions then the rate at which Sulphur is produced is low and the reaction is described as slow.
Why reaction rate changes with concentration
If the concentration of the Sodium Thiosulphate changes the speed of the reaction changes.
In dilute Sodium Thiosulphate there are not so many Sodium Thiosulphate particles. This means that there is not much chance of an acid particle and a Sodium Thiosulphate particle colliding so the production of the Sulphur is slow
Here the Sodium Thiosulphate is more concentrated. This means there are more Sodium Thiosulphate particles in the solution. There is now a greater chance of a successful collision occurring and so Sulphur is produced quickly, The reaction is fast.
