Unit 2 Practical scientific procedures and Techniques
Undertake calorimetry to study cooling curves.
Introduction
The aim of this experiment was to determine the freezing points of paraffin wax and stearic
acid using a process called calorimetry. The aim is to accurately measure the heat flow during
the transformation from the liquid to the solid state, allowing us to observe and record the
changes in the thermal energy all over the cooling process.
This process is known for its sensitivity and accuracy in measuring heat exchange, which will
provide valuable insights (understanding) into the thermophysical properties of paraffin wax
and stearic acid.
Before each experiment, we calibrated the thermometers (digital thermocouple and alcohol
thermometer). Calibration was important in these experiments because calibration is a process
to make sure that the instrument that we are using is giving us an accurate value such as
temperature.
Intermolecular forces and velocities during freezing and cooling.
In these experiments, the intermolecular forces play a significant role when the molecule is
freezing and cooling.
The transformation from a liquid state to a solid state during the cooling and freezing process is
all about interaction between the particle or molecule’s intermolecular forces and velocity.
Which is based on, as a substance cools, the kinetic energy of that elemental particles
decreases. This limiting in kinetic energy and velocity results from the loss of thermal energy.
This decreases the rate of effects on both translational and vibrational motion, by bringing the
particles closer to each other's. The decreasing is a result of strengthened intermolecular
interactions, which include van der Waals forces, dipole-dipole interactions, and hydrogen
bonding. These interactions become more important as particles approaches to each other's,
which causes an increase in attractive forces between the molecules. therefore, stronger
attractive forces can cause the change from disorder to a more organized and accurate solid
structure.
when particles slow down enough due to cold temperatures they start freezing, which leads
them to form a solid structure. This process releases heat. Understanding how intermolecular
forces and particle movements work during cooling helps us grasp how matter behaves in
separate phases and interactions between them.
Importance of Calibration
, Calibration is key for measurement and instruments as it makes sure that the results are precise
and reliable of any measuring instrument. This includes comparing a calibrated instrument to a
proven accurate source standard to identify and correct any deviations, alteration, or
inaccuracies. Regular calibration is important because equipment can lose accuracy over time
due to factors like environmental changes. Beyond maintaining measurement accuracy,
calibration also fixes confidence in the information provided by these instruments. In fields
where precision is essential, such as, healthcare, scientific research and errors in measurements
can have remarkable results for products by safety and decision-making processes.
furthermore, calibration is an essential practice that verify the principles and quality of data,
smoothly well-informed and dependable decision-making across a wide range of applications.
Steric acid investigation.
In this experiment, first we have to find the accuracy of glass thermometer.
the results we got,
Thermometer Temperature in ice bath (°C) Error value (°C)
Alcohol 4 -4 ± 0.5
Thermocouple 3.8 -3.8 ± 0.05
After calibrating the thermometers that we were using, we started our main experiment, for
that we melted the steric acid and find out its cooling rate and melting rate using a glass
thermometer.
The results we got,
Time ± 0.01 (s) Temperature ± 0.5 (°) Cal. Temperature ± 1.0 (°)
0.00 75 71
10.00 74 70
20.00 73 69
30.00 71 67
40.00 70 67
50.00 70 66
60.00 69 65
70.00 69 65
80.00 68 64
90.00 67 63
100.00 67 63
110.00 66 62
Undertake calorimetry to study cooling curves.
Introduction
The aim of this experiment was to determine the freezing points of paraffin wax and stearic
acid using a process called calorimetry. The aim is to accurately measure the heat flow during
the transformation from the liquid to the solid state, allowing us to observe and record the
changes in the thermal energy all over the cooling process.
This process is known for its sensitivity and accuracy in measuring heat exchange, which will
provide valuable insights (understanding) into the thermophysical properties of paraffin wax
and stearic acid.
Before each experiment, we calibrated the thermometers (digital thermocouple and alcohol
thermometer). Calibration was important in these experiments because calibration is a process
to make sure that the instrument that we are using is giving us an accurate value such as
temperature.
Intermolecular forces and velocities during freezing and cooling.
In these experiments, the intermolecular forces play a significant role when the molecule is
freezing and cooling.
The transformation from a liquid state to a solid state during the cooling and freezing process is
all about interaction between the particle or molecule’s intermolecular forces and velocity.
Which is based on, as a substance cools, the kinetic energy of that elemental particles
decreases. This limiting in kinetic energy and velocity results from the loss of thermal energy.
This decreases the rate of effects on both translational and vibrational motion, by bringing the
particles closer to each other's. The decreasing is a result of strengthened intermolecular
interactions, which include van der Waals forces, dipole-dipole interactions, and hydrogen
bonding. These interactions become more important as particles approaches to each other's,
which causes an increase in attractive forces between the molecules. therefore, stronger
attractive forces can cause the change from disorder to a more organized and accurate solid
structure.
when particles slow down enough due to cold temperatures they start freezing, which leads
them to form a solid structure. This process releases heat. Understanding how intermolecular
forces and particle movements work during cooling helps us grasp how matter behaves in
separate phases and interactions between them.
Importance of Calibration
, Calibration is key for measurement and instruments as it makes sure that the results are precise
and reliable of any measuring instrument. This includes comparing a calibrated instrument to a
proven accurate source standard to identify and correct any deviations, alteration, or
inaccuracies. Regular calibration is important because equipment can lose accuracy over time
due to factors like environmental changes. Beyond maintaining measurement accuracy,
calibration also fixes confidence in the information provided by these instruments. In fields
where precision is essential, such as, healthcare, scientific research and errors in measurements
can have remarkable results for products by safety and decision-making processes.
furthermore, calibration is an essential practice that verify the principles and quality of data,
smoothly well-informed and dependable decision-making across a wide range of applications.
Steric acid investigation.
In this experiment, first we have to find the accuracy of glass thermometer.
the results we got,
Thermometer Temperature in ice bath (°C) Error value (°C)
Alcohol 4 -4 ± 0.5
Thermocouple 3.8 -3.8 ± 0.05
After calibrating the thermometers that we were using, we started our main experiment, for
that we melted the steric acid and find out its cooling rate and melting rate using a glass
thermometer.
The results we got,
Time ± 0.01 (s) Temperature ± 0.5 (°) Cal. Temperature ± 1.0 (°)
0.00 75 71
10.00 74 70
20.00 73 69
30.00 71 67
40.00 70 67
50.00 70 66
60.00 69 65
70.00 69 65
80.00 68 64
90.00 67 63
100.00 67 63
110.00 66 62
