This is assignment 2B. I have received a DISTINCTION in every assignment, so a DISTINCTION overall in unit 2. I keep it simple and follow the assignment criteria, this includes practical results too.
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Cooling stearic acid and paraffin wax.................................................................................5
Results: stearic acid............................................................................................................6
.....................................................................................................................................................6
Results: paraffin wax..........................................................................................................6
Graph: stearic acid.............................................................................................................8
Graph: paraffin wax...........................................................................................................9
Stearic acid: gradient.......................................................................................................10
Paraffin wax: gradient.....................................................................................................10
What happens at a molecular level when a substance cools and freezes?........................10
Analysis............................................................................................................................10
Evaluation........................................................................................................................11
Results of other groups....................................................................................................11
Conclusion........................................................................................................................11
Bibliography.....................................................................................................................12
1
, Introduction
In this experiment I will be measuring the cooling rate of stearic acid and
paraffin wax through cooling and heating curves. Stearic acid and paraffin
wax will be used in this experiment. Stearic acid is one of the most
common long-chain fatty acids also known as octadecanoic acid. Paraffin
wax is a soft, colourless substance made from a combination of
hydrocarbon molecules comprising between twenty and forty carbon
atoms. It is obtained from petroleum, or coal. The aim of this experiment
is to determine temperature and physical changes while studying cooling
curves.
Cooling curves
A cooling curve for a substance is a graph of
the temperature variations over time as the
substance cools. The heat capacity, thermal
conductivity of the substance, and external
temperature are all factors that influence
the cooling curve's gradient. The more heat
it takes to change the temperature of a
substance, the slower it cools, and the
smaller the curve's gradient. The faster heat
is transferred, the faster the substance cools. An example of a cooling
https://bit.ly/3NBymGK
curve can be seen in figure 1.
Heating curves
A heating curve is a plot or graph in which a
substance is exposed to increasing
temperatures over time to determine how
much energy it absorbs and how its state
changes as the temperature rises. The
heating curve usually includes isolating a
system from its surroundings and seeing
how it changes as it is changed by heat in a
closed container. The system absorbs the
energy when it is heated. As a result, the
https://bit.ly/2LIhUbu
system's status is changed. An example of a heating curve can be seen in
figure 2.
Calibration
The accuracy and quality of measurements taken with a piece of
equipment is referred to as calibration. It is the process of setting up an
instrument to get a result for a sample which falls within a reasonable
range. When using specialised technologies or measuring specific
characteristics such as temperature and humidity, there is a possibility for
results and accuracy to drift over time. For reliable, accurate, and
repeatable measurements, equipment must be calibrated on a regular
basis. The purpose of calibration is to ensure the accuracy of test
equipment to reduce measurement uncertainty. Calibration reduces
measurement errors and uncertainties to an acceptable level by
quantifying and controlling them. Any instrument that will be used in a
2
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