Rates of Reaction - Sodium Thiosulphate and Hydrochloric acid
In this piece of coursework, I will study how concentration affects
the rate of reaction. I will do so by timing the reaction of Sodium
Thiosulphate with an acid. In this coursework, I will include
background knowledge, prediction, safety, results, calculations,
graphs, an analysis, conclusion and an evaluation. In my evaluation I
will comment on how reliable my results were and how I could have
improved my coursework in any possible way.
The definition of rate of reaction is ‘The speed at which a chemical
reaction takes place’. The factors that affect the rate of reaction
· Use of a catalyst
· Surface area
I will be investigating Concentration in this experiment. In a higher
concentration there are more Sodium Thiosulphate particles. This means
there is a higher number of collisions which will have enough energy
to react. This causes the rate to increase. The time it takes for a
change to take place can be measured and can be estimated. For a
reaction to take place 2 reactants must collide and the collision must
have enough energy.
I predict that as the concentration of the Sodium Thiosulphate
increases the rate of reaction will increase. This can be proved by
relating to the collision theory. I predict that as concentration is
increased the amount of time taken for the reaction is halved.
There are many safety issues that need to be considered while doing
this experiment. These include:
· Wearing safety goggles at all times. If acids or any other chemicals
are spilt, they would cause serious damage to the skin and eyes.
· Ties and long hair should be kept away from the experiment.
· If an accident occurs, tell the person Incharge.
· Any loose items must be removed.
· Stand up while doing the experiment.
· Bags or any other obstructions should be removed.
I have done a preliminary experiment to help me decide the range of
concentrations to use and how much of a difference in concentration to
leave between each one. My preliminary results also show that 5cm3 is
a low enough concentration to begin with. My knowledge tells me that
5cm3 will take longer to react because there are less sodium particles
that react with the acid. My experiment is time based and I will not
have enough time to go lower. I took 10 concentrations in the
preliminary test already, and this should show enough of a trend
already, so there is no need to do an even lower concentration, as it
would not help my experiment in any way.
· 100ml conical flask
· Different size measuring cylinders(5ml, 10ml, 50ml)
· Piece of paper.
· Blue or black pen
· Hydrochloric acid
· Sodium Thiosulphate solution
To keep this a fair test I have made sure that the acid used is the
same amount every time. Also the size of the cross on the piece of
paper is the same. The temperature is also the same because the...