If you added it to the flask using a spatula, and then quickly put the bung in, you might lose some gas before you got the bung in.Alternatively, as you pushed the bung in, you might force some air into the measuring cylinder. To start the reaction, you just need to shake the flask so that the weighing bottle falls over, and then continue shaking to make sure the catalyst mixes evenly with the solution.Tags: Computer Training Center Business PlanTones Of EssaysMarket Penetration Strategy Business PlanGood Music To Listen To While Doing HomeworkEthnic Background EssaySoap Opera ThesisDr Frank Walter Steinmeier DissertationCan You Have A Rhetorical Question In An Essay
This is repeated for a range of concentrations of the substance you are interested in.
You would need to cover a reasonably wide range of concentrations, taking perhaps 5 or so different concentrations varying from the original one down to half of it or less.
Since this is the part of the reaction you are most interested in, introducing errors here would be stupid!
You have to find a way of adding the catalyst to the hydrogen peroxide solution without changing the volume of gas collected.
Some sample reactions The catalytic decomposition of hydrogen peroxide This is a simple example of measuring the initial rate of a reaction producing a gas.
A simple set-up to do this might be: The reason for the weighing bottle containing the catalyst is to prevent introducing errors at the beginning of the experiment.Obviously, you could then repeat the process by changing something else - the concentration of a different substance, or the temperature, for example.Understanding the results We will take a simple example of an initial rate experiment where you have a gas being produced.You could also use a special flask with a divided bottom, with the catalyst in one side, and the hydrogen peroxide solution in the other. If you use a 10 cm measuring cylinder, initially full of water, you can reasonably accurately record the time taken to collect a small fixed volume of gas.You could, of course, use a small gas syringe instead.That is only a reasonable approximation if you are considering a very early stage in the reaction.The further into the reaction you go, the more the graph will start to curve.The maths of this might not be familiar to you, but you may find that you are asked to do this as a part of a practical exam or practical exercise.If it is an exam, you would probably be given help as to how to go about it.So you would convert all the values you had for rate into log(rate). I suspect that in the unlikely event of you needing it in an exam at this level, it would be given to you. You probably have to enter 2 and then press the log button, but on some calculators it might be the other way around.Convert all the values for [A] into log[A], and then plot the graph. All you need to do is find the log button on your calculator and use it to convert your numbers. If you do it the wrong way around, you will just get an error message.