Am I correct in terms of accuracy and precision with my experiment? Watch

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Report Thread starter 3 years ago
I am doing and experiment write up on the enthalpy change of combustion in alcohols and I need to do an accuracy and precision part. Is this correct???

Accuracy and Precision
The measuring equipment used in this experiment were a top-pan scale, a stopwatch, a thermometer and a measuring cylinder.
The top-pan scale was used to measure the mass of the spirit burner before and after it was burnt, the mass was recorded in grams to two decimal places to ensure that the recording was precise as possible as it provides a figure closer to the exact value of mass which then provides more accurate data for the calculations. For example with the mass of Methanol, the initial mass of the spirit lamp was recorded as 242.41g and the mass after burning was 241.45g. Meaning that the mass burnt was 0.96g (242.41-241.45g).

The stop watch was used to measure the water being heated over a repeating 30 second interval, the time was recorded to the nearest second as the stop watch went up in units of 0.01s which provided very precise recordings of time that helped to determine when the 30 seconds were reached so the temperature could be taken immediately at that time. Timing was very essential to get an accurate reading of heat as the temperature is constantly rising with time, so the temperature couldn’t have been recorded accurately without the precision of the stopwatch.

The thermometer went up in units of 0.5˚C which made it very precise when recording the temperature, the readings that were recorded also seemed accurate as there were no fluctuations and each alcohol increased at a steady rate.

The measuring cylinder did not have many divisions on the scale and the scale was not very clear so it was not precise. However since for this experiment we only needed to measure out 100cm3 of water a 100cm3 measuring cylinder was used, it was filled with water until the bottom of the meniscus touched the 100cm3 mark. This made the measurement of the water very accurate.
TSR Jessica
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Report 3 years ago
Sorry you've not had any responses about this. Are you sure you’ve posted in the right place? Posting in the specific Study Help forum should help get responses.

I'm going to quote in Tank Girl now so she can move your thread to the right place if it's needed. :yy:

(Original post by Tank Girl)
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Report 3 years ago
Error bar? What level is this? If AS then it would be nice for you to include error calculations because it isn't going to actually be 0.96s

And as for the time you couldn't have recorded time to a hundredth of a second... Due to human reactions it's probably precise to 1 second at best

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