# To find out how different concentrations of hydrochloric acid reacts with marble chips.

Science Coursework: 1

Variables:

The reaction rate is affected by:

Increasing temperature,

Stirring,

Volume,

Concentration of reactions,

Surface area, the marble chips are different sizes

Amount of reactants.

Aim:

My aim is to find out how different concentrations of hydrochloric acid reacts with marble chips.

Preliminary test:

For this test I used 4 marble chips, 20ml of hydrochloric acid and a 100ml measuring tube full of water. My aim is to find out how long it takes gas to fill up the tube by timing it until all the water has gone from the tube. The gas is produced by 4 marble chips been put in the acid which produces gas.

Hydrochloric acid + calcium carbonate --> calcium chloride+ carbon dioxide.

Sceintific knowledge that will help with my prediction:

> When a reaction occurs the particles of two reations must collide.

> A much more conentrated solution has more particles per cm /ml.

> So, if there are more particles in both solutions and solid the particles will be able to collide more easily and so, making the reaction quicker.

> The particles must have a lot more energy so that they move fast and when they collide with each other they don't just ...

#### Here's what a teacher thought of this essay

** Planning The candidate has carried out an experiment to investigate the effect of changing concentration on rate of reaction. The experiment was planned with a stated hypothesis and a clear idea of how this was to be tested. The planned method was lacking in key scientific details and failed to ensure all the key variables were controlled. Carrying out The candidate carried out a reasonable number of repeats on an acceptable range of the independent variable but the recording of results was poor with lack of clear headings and units in the table. The graph was not included. Analysis and Evaluation The report's conclusion is limited and there was no evaluation used to look at the method used and to suggest improvements. The conclusion would be improved by linking it more closely to the aim of the experiment, stating the effect of concentration on rate of reaction.