Rates of reactions between HCL and magnesium ribbon.
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Rates of reactions between HCL and magnesium ribbon Aim I plan to investigate the effect of concentration of acid, in the reaction between dilute hydrochloric acid and magnesium ribbon. The rate of a chemical reaction is a measure of how fast the reaction takes place. It is important to know that a rapid reaction is completed in a short period of time. Some reactions are very fast, for example; the formation of silver chloride precipitates when silver nitrate and hydrochloric acid solutions are mixed. In this investigation I will test different concentrations of acid reacting with magnesium. Prediction My prediction is that as the concentration of the hydrochloric acid increases, the time taken for the magnesium to disappear decreases. I predict that when the concentration of the hydrochloric acid doubles, the rate of the reaction doubles. Linking prediction to theory Reaction rate and concentration. The collision theory describes how the rate of reaction increases (the time taken for the magnesium ribbon to disappear when it is reacted with hydrochloric acid)
This way the rate of reaction(the time taken for the magnesium to disappear) was measured accurately for a fair test. Results The results for the time taken for magnesium to disappear when it is placed in different concentrations of acid are summarised below. Analysis of results From the results in the table and the graph we can see a steady increase in the rate of reaction as the concentration of the acid decreases. This complies with my prediction. The graph shows that there is an increase in the rate of reaction as the concentration increases because the graph has it's largest gradient or it is steepest at this point. When the graph was made into 1/time the result should have been a straight line graph but it did not turn out this way even though concentration~1/time. This 1/time graph could be wrong because of inaccurate results so there seems to be no relationship between the concentration graph and the 1/time graph.
particles which have to have the activation energy because they are the ones that are moving and bombarding the magnesium particles to produce magnesium chloride. The graph for 1/time had the form of an s curve and it did have some relationship with the other graph. Evaluation There are many reasons why our results for the 1/time graph did not prove the point that concentration~1/time, such as 1. When the reaction takes place bubbles of H2 are given off, which might stay around the magnesium, which therefore reduces the surface area of the magnesium and so the acid cannot react properly so this affects the results. 2. We could have controlled factors in the investigation better (e.g. the stirring of the solution because if this is not done properly it can lead to incorrect results). 3. Using larger concentrations of acid would give a bigger more accurate conclusion instead of just using 10ml test tubes use 1litre test tubes, this way graphs would be more spaced out and give an accurate form or curve.
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