Investigating Whether There is a Link Between the Concentration of Thiosulphate Used in the Reaction with Hydrochloric Acid and the Time Taken for the

Investigating Whether There is a Link Between the Concentration of Thiosulphate Used in the Reaction with Hydrochloric Acid and the Time Taken for the Reaction to Occur

Previous helpful knowledge:

The rate of reaction tells us how quickly a chemical reaction takes to

occur. Chemical reactions take place over different time intervals and

involve reactants forming products.

Certain methods can alter the rate of reaction, such as:

* Adding a catalyst

* Changing in the surface area of a solid

* Changes in the temperature

* Changes in the concentration

I know, from previous experiments, that sulphur is formed when HCL is

added to NaSO solution. Between the two reactants, a reaction takes

place. This produces sulphur which precipitates out of the solution as

a white-ish, and then yellow solid.

Developing a plan:

When studying the rates of reactions, we will monitor the time in

which Sodium Thiosulphate react with Hydrochloric acid. In order to do

this we will use a piece of paper with an X drawn on it and record how

long it takes for the X to become obscured by the solution. This will

show that the particles have colided and have reacted with sufficient

energy. When the substances react with one another, the solution turns

opaque so the X will be hidden. We will record from the time that the

HCL is added to NaSO, until the X is no longer visable. We will use

these recordings to find the rate of reaction.

What do you predict will happen?

I predict that when the NaSO is of higher concentration, the rate of

reaction will be quicker for the reason that, the higher the

concentration, the greater the probability of collision – consequently

the rate will be faster.

What are the variables and what must you keep constant?

Variable