Does concentration effect the heat of neutralisation between sodium hydroxide and hydrochloric acid?

Plan

I will try to investigate accurately whether concentration affects the heat of neutralisation between Sodium Hydroxide and Hydrochloric acid.

To do this I will need to consider the safety precautions and how I will make sure that this is an accurate and fair test. I also will also look at the equipment that I will use during the experiment.

Safety

To make sure this experiment is as safe as possible I will make sure that I wear safety goggles whilst doing the experiment and while I am handling the chemicals. This is so that if the acid splashes or if any explosions occur I will not damage my eyes.

Accuracy

I will try to keep the starting temperature the same every time. I will try and achieve this by taking the first starting temperature and writing it in my results table. The next time I come to take the starting temperature, I will try and get that temperature the same as my starting temperature. If perhaps the temperature is too low then I shall place the test tube in a shallow bath of warm water, the heat will conduct warming the Sodium Hydroxide to the required starting temperature. If the temperature is too high I will do exactly the same but with cold water.

I will also try and make sure that I use a dry, and thoroughly washed clean test tube. This will ensure that I don’t concur any interference from other substances i.e. chemicals that might be left in there from other experiments or any liquid that could weaken the Sodium Hydroxide, making the test inaccurate. I shall make sure that there isn’t any Sodium Hydroxide or Hydrochloric acid in there, which could either change the strength of the chemical or start the neutralization early which would produce inaccurate results.

Method

I am going to try and investigate whether ...

This is a preview of the whole essay

Method

I am going to try and investigate whether different strength acids make a difference to the amount of heat the neutralization gives off. I will test five different strengths of Hydrochloric acid. They will be; 1M, 0.8M, 0.6M, 0.4M and 0.2M. I have chosen these strengths because they will give me enough results to analyse and produce an accurate graph. I have also chosen these measurements because of the risks. If I had of chosen strengths of higher Moles there would be a safety hazard because I am doing this experiment in the school lab. I would prefer to use the measurements I have chosen because I feel that I would be safer and get better results.

I will measure out 5cm of 0.2m Sodium Hydroxide and pour it into a test tube. I will then take the temperature of this and write it in my results table. Then, I will measure out 5cm of the Hydrochloric acid, in a clean measuring cylinder that I will have cleaned and dried as possible. I will then pour it into the Sodium Hydroxide and read the thermometer and note down the highest temperature that it reaches. Repeating this procedure for all the Moles until I have collected enough data for my results table.

I am going to make the prediction that the stronger the acid the more heat the neutralisation will produce.

For example the 0.4M acid will produce more heat than the 0.2M acid.

The reason for this is because there are more acid particles in the 0.4M Hydrochloric acid than in the 0.2M hydrochloric acid. This means that there are more acid particles to collide with and to neutralise the Sodium Hydroxide. There will be more particles colliding, and reacting, meaning the temperature will rise more in a stronger acid.

Conclusion

During this experiment I have found out that the more Moles the acid has the more heat is produced from the reaction. My graph shows this. The reason for this is because of the amount of acid particles in the solution. The 0.2m acid has less acid particles in the solution than the 1m solution; therefore there are less acid particles colliding with the Sodium Hydroxide particles, making the temperature rise less than the 1m solution. There was little change in the average rise in temperature between the 0.2m, 0.4m and the 0.6m solutions of Hydrochloric acid, whereas there was a significantly bigger rise between the 1m and the 0.8m Hydrochloric acid solutions. I believe this is because all of the different strength acids had roughly the same reaction time, so if the 1m solution has the same reaction time as the 0.8m solution it means that during that time more particles are reacting. I think it is for this reason that I have a curved line of best fit on my graph when I plot my average results from this experiment.

Evaluation

This experiment was a success as it proved my prediction right. I was a bit concerned that although I tried lots of methods to try and get the starting temperatures to the same, I couldn’t, I would try harder to do this I was to do this experiment again. The test tubes with the higher starting temperature could have produced slightly higher temperature rises because the particles had more energy than the cooler ones, making the collisions between the particles more frequent, making the temperature raise more. If I was to do the experiment again I would prefer to do it with stronger Chemicals as I believe I will get better results.

After my main experiment I conducted another little experiment to see what would happen if I mixed 1M Sodium Hydroxide acid with 2M Hydrochloric acid. I would have expected the rise in temperature to be no more than the 1m Hydrochloric acid because there is only the same amount of Sodium Hydroxide particles for the Hydrochloric acid particles to react with. The noticeable rise is because there was more Hydrochloric acid particles in the solution, there was always more chance of the Sodium Hydroxide particles colliding with a Hydrochloric article. So there are more particles colliding at any one time, I believe that it is for this that the rise is more than expected.