Preliminary Results

Here is the word and symbol equation for the reaction:

Sodium + Hydrochloric Sulphur + Sulphur + Water + Sodium

Thiosulphate acid Dioxide Chloride

Na2S2O3 + 2HCl S + SO2 + H2O + 2NaCl

As you can see from the word equation there are a lot of bonds to break in this experiment so the more "HCl's" there are the quicker it will be to break the Sodium Thiosulphate. You can also see that two "HCl's" are needed to successfully break down one Sodium Thiosulphate molecule. So this would mean that the more "HCl's" the better. So for my experiment I will create five different measurements of Hydrochloric acid (0.1M-0.5M in steps of 0.1M) and react it with Sodium Thiosulphate and time how long it takes for the "X" to disappear under the beaker. I will always use 50ml3 Sodium Thiosulphate and 5ml3 Hydrochloric acid. I will then record my results onto a table and then on to a graph. To make my experiment I will measure the time to two decimal places and I will measure the quantity of Sodium Thiosulphate with a measuring cylinder and the Hydrochloric acid with a Pipette. I will also do three trials for each measurement to make it more reliable. To ensure my safety in this experiment I will wear goggles and avoid touching the acid.

In this experiment I predict that when I increase the concentration of Hydrochloric acid the rate of reaction will increase. This is because at low concentration there are less particles to collide whereas at high concentration there are lots more particles to collide i.e. if there is a reaction where 100 successful collisions have to occur for the reaction to be complete and you only have ten particles, it will take a lot longer than if you had 100 particles to collide. If you increased