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What is calorimetry and where is it used?
(See https://en.wikipedia.org/wiki/Calorimetry for where I got part of the definition from.)
This is the scientific way used to measure the transmission of heat either to or from a
substance during a chemical reaction. By doing calorimetry it can tell us if the reaction
which has taken place is endothermic (the release of energy/heat) or exothermic (the
absorption of energy/heat). The entire process of calorimetry is vital for humans to
function daily, as it regulates and preserves things like metabolic rates and body
temperature. In the context of an industrial site, calorimetry is very popular in the coal
business (e.g., coal fired power stations, iron plants, etc.)
Aim for this practical
While I carry out the calorimetric procedure, I will be looking to determine any physical
changes, change in temperature and to study cooling curves using two substances:
stearic acid and paraffin wax.
I will start by explaining how to perform the procedure of calibrating the
thermometers then continue into how to perform the method of both stearic acid and
paraffin wax and analysis both results.
Thermometers
This is a scientific apparatus, which can measure the
temperature of all three states of matter. Standard
thermometers usually measure the temperature using the
Degrees Celsius scale (°C), the two types of thermometers we
used were liquid filled thermometers and digital
thermometers. Inside the liquid filled thermometer, the most
common type of liquid within it is either mercury or ethanol (I
used mercury). The downside to using the liquid filled
thermometer is the liquid which could limit the results obtained by the thermometer.
An example of this could occur when, mercury tries to measure the
temperature of a substance which is below -38.83°C it will not be able to
produce a result due to mercury freezing at that temperature. Likewise,
alcohols – similar to ethanol- tend to boil at 78°C consequentially not
allowing the temperature of a substance which happens to have a
temperature at 78°C or higher to be chronicled; these however are much
cheaper than most temperature measurement devices and are generally
most convenient. On the other hand, a viable substitute to the liquid filled
thermometer is a digital thermometer, with this working by using a
thermistor- a device that – depending on the temperature – changes its resistance
which then displays the reading of the substance, these usually give a more accurate
value than liquid filled thermometers.
, A Report on Calorimetry Procedures and Practises
Calibration of thermometers
The process of calibrating the thermometers serves as an integral part to getting the
practical correct as this allows us to reduce the chance of any uncertainties whilst
doing the measurements and minor mistakes which happen as a result of the
thermometer. While choosing a thermometer, it is essential that it should be the finest
thermometer you can seek. The calibration procedure is indispensable as it allows us
to make sure that the thermometers are working correctly as even the slightest of
margins will have a knock-on affect on the results we are trying to obtain.
How to calibrate
1. Make sure to add ice into a beaker (250cm3) along with 100 cm3 of cold water
and give time for the ice to melt – approximately 2-3 minutes- this allows the
temperature of the water to drop.
2. When the ice bath is formed, place the thermometers (digital and liquid filled)
into the beaker and give time for the thermometer to obtain the results. The
thermometers have been correctly calibrated if the thermometers read 0°C
Once the method above has been completed do the exact same with boiling water and
the thermometer this time should read 100°C.
Calibrating Results
Temperatur (°C)
e
Digital Liquid
1 2 3 1 2 3
Ice Water 6.3°C 3.4°C 4.3°C 8°C 4°C 7°C
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