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2.2 assignment- Undertake calorimetry to study cooling curve
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UNIT 2 LEARNING AIM B: UNDERTAKE CALORIMETRY TO STUDY COOLING CURVES.Calorimeter is used to measure the temperature during the reaction of the chemical which is heated. In
this assignment I will talk about thermometers and discuss the experiment of measuring temperature of
steric acid and paraffin wax from liquid to solid, comparing and evaluating different other results with
my results.
Resubmission is highlighted with yellow.
COOLING CURVE FOR STEARIC ACID AND PARAFFIN WAX.
Stearic acid is a long chain saturated fatty acid. Stearic acid is also known as octadecanoic acid or
stearophanic acid. This saturated fatty acid is found in plants and animal fats. Stearic acid is made up
from fats and oils with the help of hot water. It has a boiling point of 361 oC and 69.3oC of melting point.
Paraffin wax is made from saturated hydrocarbons. Paraffin wax is used to make candles. At room
temperature it is solid, soft and white. It can melt easily and quickly. Paraffin wax is made up of a
mixture of hydrocarbon molecules which are alkanes. They melt between 46-68 oC and have a boiling
point of 370oC.
First, before doing the practical you need to calibrate the thermometer and know if it is accurate and
useful. To calibrate you need to fill the beaker with ice and tap water, it needs to be more ice than water
because the boiling point of water is 100 oC which can lead you to a wrong calibration for your
thermometer to use it in cooling curves. The water used to calibrate the thermometer needs to be pure
otherwise this results in an error calibration.
Risk assessment for steric acid and paraffin wax.
Hazard Risk Solution
Water bath Burn your skin if the water spillage Avoid touching the plate when it is
in the skin. hot and carefully handle the kettle
Touching the hot plate could cause which has hot water
burn
Alcohol thermometer Irritant if the liquid of alcohol is Wash your mouth quickly and drink
swallowed into your body and may water otherwise you need medical
contaminate attention
Stearic acid Irritant to eyes or skin if it is in Wear safety goggles or gloves to
contact minimise irritant or wash your hands
with water.
Thermistor (digital Dropping down the thermometer Place the thermometer safely on the
thermometer) will cause damage of the equipment table and avoid it to put it into the
and may not produce correct edge of the table.
results.
Paraffin wax Irritant to eyes and cause Wear goggles and gloves to reduce
respiratory problems any risk and do not swallow the wax
Glass beaker Breaking glass could lead to cut Keep the beaker away from the edge
your skin of the table
Test tube with the Clamp the test tube properly Make sure you clam the test tube with
sample otherwise will lead to the sample and make sure you clamp
contamination it little bit tight.
, Method for steric acid and paraffin wax.
1. Put about 150 cm3 water into the beaker.
2. Heat it until the water just starts to boil.
3. Add tube with sample to beaker, until it turns to liquid.
4. Use the clamp stand to lift the tube from the hot water.
5. Measure temperature every 30s until it becomes solid.
6. Do not move the thermometer when it is solid.
Results table for steric acid.
Time (every 30 seconds) Temperature (oC)
30 sec 71
60 sec 67
90 sec 63
120 sec 60
150 sec 58
180 sec 57
210 sec 56
240 sec 55
270 sec 54
300 sec 54
330 sec 54
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