Rates of Reaction in Antacids
Aim
I plan to investigate the effectiveness of indigestion tablet on HCl.
I will take five different tablets containing a specific pH of alkali and discover how long it takes for the indigestion tablet to neutralise the acid. The test will tell me which is the fastest acting tablet is in the case of indigestion.
Antacids
Antacids are bases and most of them react on the excess build up of stomach acid and neutralises the acid. The most common of these bases are hydroxides, carbonates or bio carbonates.
Neutralisation
If you have a weak acid you can eliminate the acidic pH by combining it with a weak alkali. Neutralisation is a chemical reaction which is caused by combining both an acid and an alkali, this reaction causes both the solutions to cancel each other out, and this reaction leaves you with water and salt. Neutralisation is simply the combination of hydroxide ions OH and hydrogen ions H+ this process leaves you with the molecule H2O and forms salt.
A Catalyst
Catalyst are use to speed up a reaction without being used up. In some reaction like digestion catalyst are essentially needed to speed the process or digestion would take too long to gain nutrients.
A catalyst breaks down a substance to provide a larger surface area to speed up the process.
The Rate of Reaction
The amount of time the reaction occurs.
Magnesium + hydrochloric acid → Magnesium Chloride + Hydrogen
This equation gives me two possible methods of recording the rate of reaction:
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Quality of writing
Spelling, punctuation and grammar are all done to a very good standard. The tone of the piece is perfect and the layout is very easy to read.
Level of analysis
The aim of the investigation is explained well to set the experiment off. The candidate explains neutralisation in relation to the experiment well, the catalyst part is not needed as it does not directly relate to the experiment or what the candidate is trying to find out. Rates and collision theory are explained well, but again they are not directly related to the experiment, and the links should be made to make the essay flow better, and show the relevance to the experiment about to be carried out. The candidate explains well how they are going to account for factors which may affect the results of the experiment and this should be included to show a better understanding of the experiment and make the results more reliable. The candidate provides an accurate results table and a good graph. They account for what may have gone wrong in the experiment through the evaluation well.
Response to question
The response to the question is done very well. The only problem was that the focus at the start was not quite right as discussed below, with sections that were not directly relevant to the experiment being included. To make them more relevant the candidate should have tried to link theory to practice throughout the background research.