# Essay Sample on The levels of hydrogen gas

As if I use the catalyst all I will be doing is increasing the amount of magnesium used each time this is the same as the surface area because if I choose to vary the surface area all I was going to do was again increase the amount of magnesium used which would results in more surface for the articles but as this does not give be qualified results I am not doing it so this same principle affects me if I were to vary the catalyst so there is no point because then there would be no point of me doing my experiment if I am not able to plot my results down properly.

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So my overall choice that I have made is going to be to vary the concentration, although it is not straight forward to choose the concentration as my variable because when sulphuric acid is diluted it produces a very vigorous reaction and this is what I am going to have to do if I want to change the concentration. I am going to have to add water to dilute the concentration each time so that I get a decrease in the levels of concentrations that I use.

It is possible to work with water and the sulphuric acid, but lots of precautions would need to be taken and what will need to be done is that the acid will need to be added to the cold water slowly, and it should always be that way around it should never be to add the cold water to the sulpuric acid. It is also possible to vary the concentration because a bung will be placed over the beaker which will prevent any splashes to come out of it so all the reaction will be able to stay inside the beaker and not able to come in contact with us.

Prediction: What I predict is that the more concentrated the solution is the more reaction would take place which would mean that more hydrogen would be produced and as the concentration levels decrease the reactions would become weaker and less hydrogen would be produced. I base this prediction on the collision theory, as the stronger the solution means that there would be more particles per dmi?? ,which would mean that they would be able to collide with each other more often than when the solution is a lot weaker.

The weak solution would mean that it would be a lot harder for the important particles to collide with each other as there would also be water particles in the solution rather than pure So4. i also think that as time goes on the reaction would start to increase in producing volume of hydrogen as the magnesium and the sulphuric acid would have had more time to react. Preliminary testing: I will be conducting a preliminary test so that I am able to make sure that everything goes well and that I receive good enough results when varying the concentration. Apparatus that will be used when conducting this experiment:  Conical flask.

Delivery tube  Rubber bung  Wooden blocks  Water bath  Measuring tube In this experiment I will be measuring the reaction every 30 seconds up to 210 seconds. I have chosen to record the results after each 30 seconds because I feel that it is the correct interval to measure the reaction at. By going up to 210 seconds I will be able to analyse what happens to the reaction as time goes on so does the hydrogen produced increase or decrease in levels also going up to 210 seconds provides me with a set of 7 results per concentration which would enable me to get a good average and it is a good amount of data to be able to analyse.

I have chosen the concentrations of 100%, 9:1, 8:2, 7:3. The way in which the concentrations were worked out is that we are allowed to have 1x molar of sulphuric acid which is basically 10cm of acid = 100%. So to work out the concentrations we wanted all we did is what ever % we wanted we divided it by 100. so we did 90%, 80% and 70% this gave me 9, 8 and 7 as the concentration of sulphuric acid then all I did was make the percentages to 100 so 9 and 1 is 10 therefore it is 100% and so on, the numbers 1, 2 and 3 is the cm of water that I am going to used to dilute the sulphuric acid.

Safety precautions: During this experiment I will need to take precautions, precautions on safety and accuracy. my safety precautions are that I need to wear safety goggles at all times this is because we are using sulphuric acid and it is harmful to the eye so to prevent it entering the eye goggles will reduce the chances . Alertness needs to be maintained by everyone this is because if you are not listening or paying attention to one and other than the chances of having an accident increases.

Precautions of spillages should be taken because the acid is harmful it would be advisable not to spill it on the benches because then it can get in contact with skin or in eyes if people do not know it is there it can be passed along anywhere . Precautions should also be taken when moving around the room; you should not travel across the lab with acid in your hand if possible because if you trip then it would be dangerous to not only the person carrying the acid but to others. Bags should be put on the side so nobody falls over them, stools should be tucked under.

You should stand up when conducting the experiment as it is easier to see and to do things. Precautions that need to be taken with accuracy: would be to make sure that the acid is measured out correctly, to the nearest centimeter as possible of course it can not be absolutely perfect as it is bound to be 1cm +/-. Also precautions will need to be taken to remember to change the water in the glass tube every time the results are recorded for a set of concentrations as then it would not be a fair test.

We will also need to remember to wash out the conical flask each time we are finished with a concentration as then it would not be a fair test if pieces of magnesium are left inside or some acid is left inside. When weighing the magnesium we should always have the weight precise as this is the one element that we are able to have precise because the weighing scales are accurate and we can add or subtract even brake the pieces to make sure that they weigh exactly what we want them to.

Other precautions of accuracy would be to make sure when timing the reaction the results are read off at the time that they are meant to obviously like when measuring the concentrations it is hard to read off the results exactly on time as time does not stop and wait for you, but they should be read off as near to the time as possible and the results read off should also be as accurate as possible +/- a cm should not make a difference but major mishaps would make a difference to the overall results. During this experiment we should also take in consideration the element of fair testing:

The fair testing that should be taken into consideration is:  The conical flask should be washed thoroughly after each test to ensure no pieces of magnesium or sulphuric acid exists inside.  The amount of magnesium should be kept constant. The time that has been set should not be changed during the experiment; we should stick to one timing scheme and not change it.  The water in the glass tube should always be filled right to the top which is over 10cm when put upside down this is so that if any water spills during the process of turning the tube upside down it will not pass the 1cm mark.

Water in the plastic measuring cylinder should also be changed each time to ensure fair testing. Method: Firstly what we did was to collect all the equipment need list of the equipment is listed above. Then we set it up like this: Diagram: What we had to do is first we filled the tub with water and placed it to one side of the bench, whilst this was going on someone was setting up the conical flask and the delivery tube.

What we had to do for this is collect two wooden blocks and place them on the bench first and then place the conical flask on top of this, this is because otherwise the delivery tube would not be able to reach the bottom of the glass burette because it would have been to low. We then has to get two little measuring cylinders and start to measure out the concentrations for the first one we were using 100% sulphuric acid so we did not need to measure out any water, so we measured out 10cm of the acid and then went to weighed the magnesium turnings out.

We decided to used 0. 2g for the preliminary testing and see what happens from there. So when we had all the little elements ready we had to fill the plastic measuring cylinder up with water and carefully place it upside down in the tub full of water upside down, being careful that only a limited amount of water falls out as little as possible sp that we can make it a fair test. The delivery tube had to be placed under the measuring cylinder as you can see in the diagram.

Once everything is ready then add the sulphuric acid and the magnesium together, the rubber bung should then be placed on top this should be a fast process as once the acid comes in contact with the magnesium the reaction starts, so the stopwatch has to be placed on as soon as possible so that the reaction can stay inside the conical flask and so that oxygen is not able to come in contact with the magnesium other wise there would be two reactions happening.

Once the reaction has started to take place one person must always hold the glass burette as it will not stand up on its own and the other person must keep a record on the time, after every 30 seconds we recorded the amount that the water had decreased by and so no until 210 seconds. This process has to repeat three more times because overall four different concentrations have to be used and at the end of each concentration what we did was we made sure we washed out the conical flask and filled up the water in the glass burette again.