An Investigation into the heat changes when acids and alkalis are mixed.
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Introduction
An Investigation into the heat changes when acids and alkalis are mixed. Simple Procedure: The aim of this experiment is to investigate how the heat capacity changes when different combinations of weak and strong acids and alkalis react. In order to do this an acid of volume 40cm3 was placed in a polyester cup (was placed inside a beaker) which contains 40 cm3 of alkaline and by using a thermometer the temperature of the two substances were taken when they had reached a constant temperature. By using this temperature the heat capacity of the reaction was calculated. A diagram of the apparatus used in order to conduct this experiment is shown below: There are basically three stages to each experiment being conducted. The apparatus as illustrated above are going to be used. There are going to be four experiments conducted as shown below: The Strength of Substances Being Tested. ...read more.
Middle
2) Make sure that the same type (same area and same material) of cup is used in place of each experiment. Explanation: Again by insuring that the same type of cup is used in each experiment it removes variables such as surface area from each experiment. 3) The cup is placed in a beaker, when swirling the two mixture in the cup care must be taken in order to ensure that one does not put ones hand around the beaker as this may warm up the mixture in the beaker from the body heat which is generated. It is therefore advisable to use the thermometer in order to mix the substances. Explanation: This again is put in order to ensure that extra heat does not affect the experiment in any way and the only variable is the strengths and weakness of each acid or alkali. ...read more.
Conclusion
OH-(aq) OH-(aq) Table of Results: Reaction Experiment 1 Experiment 2 Starting Temperature (�C) End Temperature ( � C) Temperature Change Starting Temperature ( �C) End Temperature (�C) Temperature change. Average Temperature change. NaOH+ HCl 16.5 29.5 13.0 17.0 29.7 12.7 12.85 NaOH + CH3COOH 16.6 29.0 12.4 18.5 31.0 12.5 12.45 NH4OH+ CH3COOH 17.5 29.5 12.0 17.0 29.5 12.5 12.25 NH4OH+ HCl 16.8 29.4 12.6 17.0 30.0 13 12.80 Some Safety Points Whilst doing the experiment some safety points had to be considered as shown below: - Firstly at all times safety goggles were worn - to prevent any chance of these chemicals coming in contact with the eyes - It was advisable to have good ventilation in the room where the experiment was being conducted. This is because it was found that Ammonium Hydroxide has a very potent smell. - The chemical Sodium Hydroxide is corrosive therefore, hands must be washed carefully. - The thermometer in use during the experiment was a mercury thermometer therefore extra care was taken in order to not break it. Nabil Choudhury 11C Planning ...read more.
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