To investigate the effects of the concentration of Hydrochloric acid on the rate of reaction with marble chips.

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Chemistry Coursework

Aim –

To investigate the effects of the concentration of Hydrochloric acid on the rate of reaction with marble chips.

Prediction -

The rate of reaction is affected by four different factors:

  • Concentration of reactant
  • Temperature
  • Surface area
  • Catalyst

In order for the reaction to take place, the particles must have enough energy to collide.  The higher the concentration of the acid, the more particles there are more collisions, which means it will break down quicker.

An increase in temperature will make the particles move about more.  This increase in movement will result in more collisions.

The larger the surface area of the solid reactant (marble chips) means the acid particles have a larger area to work on, which means it will be broken down faster because there will be more collisions.

A catalyst works by giving the reacting surface something to stick to, where they can collide with each other.  This increases the number of collisions.

I used the NEAB Modular Science Revision guide to research collision theory to understand what it is and found the above diagrams.

My prediction uses different concentrations of acid.  I predict that as I increase the concentration of acid the rate at which the marble chips are broken down will also increase.

I predict that the actual graphs will look like the diagram below.  This is because there will be no gas produced at 0 seconds because the acid and the marble chips are not yet reacting.  After this point the gradient of the graph will increase, due to the sudden reaction of the marble and acid.  The gradient will be steepest on the graphs for the higher concentrations of acid. The graph will begin to level out towards the end of the experiment, as all the marble will have decomposed.

Fair Test –

To keep the experiment fair, we will keep the following things the same in each experiment:

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  • Mass of marble chips – so that the reactivity is similar

  • We will conduct two experiments for each concentration, so that we can find the average of the two and get a more accurate and reliable result
  • Use similar sized and shaped pieces of marble – to make sure the surface area of the chips does not become a factor in how fast the reaction is
  • Use the same bottle of acid for each experiment in case the pH of it varies from different sources
  • Conduct all experiments at room temperature – so that the temperature does not affect ...

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