Essay
UNIT 2- Calorimetry
- Institution
- PEARSON (PEARSON)
Essay UNIT 2- Laboratory Techniques & their application/ calorimetry freezing point and boiling point of acids cooling curve for steric acid and paraffin acid
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CALORIMETRYCalorimetry is the measurement of the amount of heat released (exothermic) or absorbed
(endothermic) during a chemical reaction. Calorimetry is also part of our everyday life by
controlling the metabolic rates in humans and therefore helps maintaining functions in the
body such as body temperature. I will be talking about how to use colorimetry technique for
cooling curves of a solid substance.
Calibration is a skill I gained during unit 2, and I can understand now how important it is to
calibrate the equipment before using it in any experiment. The main reason for calibration is to
have a guarantee that the equipment we are using will give results closest to the true values.
Thermomete Rough 1st reading 2nd reading Average
r type
Digital 0.1 0.0 0.0 0.03
Freezing Mercury 0.0 0.0 0.0 0.0
point (blue)
Alcohol (red) 0.0 0.0 0.0 0.0
Digital 87.8 93 93.8 91.5
Boiling point Mercury 84 90 90 88
(blue)
Alcohol (red) 88 90 95 91
Before going directly and using the acids we measure heat loss with a mercury thermometer.
First, we put the thermometer on ice until it reached 0 degrees while we were heating the
water in a kettle. Then I put the hot water on a clean beaker, I cleaned the rest of ice in the
thermometer with clean tissue and rapidly put on the beaker contained hot water and I started
my stopwatch. I immediately covered the beaker with Styrofoam to avoid quick heat loss, which
could have been a problem to my results. Styrofoam is a good insulator because it traps about
98% of the air in their small pockets and as air is a bad conductor of heat, it gives advantages
for the Styrofoam preventing heat transfer. I recorded the temperature for each minute for
about 15 minutes and I repeated the same steps one more time and I found the average.
Calibration is a key step before starting any experiment to minimize any uncertain
measurements. It can also improve safety, for example when creating solutions for medical
purposes. Small inaccuracies can cause large consequences. Calibration is also to ensure longer
,life in equipment. Calibrating any equipment is basically setting it back to its original standard
so that you can keep using it. I was able to compare my results with the other group and I might
have made a mistake while measuring the digital, because they have an average of 0, but I have
an average of 0.3. So, I believe that if I had repeated the calibration again for each of them, I
would have had better results. They also got a little higher value than mine for the boiling point
of mercury for just 0.5 higher. But for the other thermometers, I got a higher value for boiling
point for digital (1 degree more) and alcohol (12 degrees higher). So, I am sure I was more
careful while taking the readings. And I avoid the parallax error but looking at the temperature
with a direct line of sight.
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