Cash4Coursework has been rebranded ‘FreeCoursework.info’ - Visit us to download coursework for free and to earn money from your old coursework!
View this page at Freecoursework.info
The determining of a rate equation from the reaction of sodium thiosulphate with hydrochloric acid - page 8
Keywords: The determining of a rate equation from the reaction of sodium thiosulphate with hydrochloric acid
By Carlitob10 on 04/11/2006 11:57:07
Level: A Level (Year 13)
Page Number: 8 of 8 pages: 1 2 3 4 5 6 7 8This would obviously have helped to detect any anomalies much earlier.
• I have tried to restrict all calculations to a sensible and meaningful number of significant figures, as a consequence of the possible errors and inaccuracies mentioned above.
Different kinds of error:
Several kinds of errors are usually present in experimental data. Their effects on the desired results can range from insignificant to disastrous, depending on how well they are understood and accounted for.
Systematic errors are consistent effects which change the system under study or the measurements you make on it. They can consist of:
• Uncalibrated instruments (balances, etc.)
• Impure reagents
• Leaks
• Temperature effects not accounted for
Systematic error affects the accuracy of an experiment but not the precision. Repeated trials and statistical analysis are of no use in eliminating its effects. Careful experimental design and execution is the sole approach to reducing systematic error. In this particular experiment, systematic error could have come from the temperature of the environment, which I was unable to control. Indeed, I noticed that, as the experimental session continued, the atmosphere in the laboratory did seem to warm up. I do not think that there were other factors which could have caused drastic systematic error in this case.
Random error arises from mechanical vibrations in the apparatus, electrical noise, uncertainty in reading of scale pointers, and other “fluctuations”. It can be characterized, and sometimes reduced, by repeated (at least three) trials of an experiment. Note that random error affects the precision of an experiment and to a lesser extent its accuracy. I have already remarked that I would have liked to perform more replicates of the experiment.
Sources of information:
Calculations in AS/A Level Chemistry by Jim Clark. Pages 136-138
http://www.shodor.org/UNChem/advanced/kin/index.html
Last 5 comments…
There have been no comments posted for this article, but you need to register if you want to be the first!