BTEC Chemistry- Unit 2: practical scientific procedures and techniques
Section B- Keeping up with the standards
Practical for the cooling of stearic acid and paraffin wax
Method for the cooling of stearic acid and paraffin wax:
Apparatus required:
A test tube
Boiling tube
A water bath, which has been already set to 75 degrees Celsius.
A thermometer
Two test tube racks
Stearic Acid
Paraffin wax
Stopwatch
Stearic acid
Firstly, put stearic acid into a test tube and then place into a test tube rack into a water
bath, which has already been set to 75 degrees Celsius. Next, put a test tube onto a table
and put a thermometer in the test tube that contains the stearic acid. Then take the test
tube out of the water bath and place it into the test tube rack on the table. The next step is
to measure the temperature of the stearic acid; this is to ensure that the stearic acid is at its
highest temperature before its temperature starts to decrease. After you have done this,
start a stopwatch. You then need to measure and record the temperature for the
temperature of the stearic acid at 30 second intervals. Do this until the stearic acid appears
to be at a solid state, or until the temperature stops decreasing and remains stationary. The
last step involves placing the test tube back into the water bath and waiting for it to melt,
then removing the thermometer out of it afterwards, so that the thermometer doesn’t
shatter.
Paraffin Wax
The steps for the method used to investigate the cooling of paraffin wax is the same as the
steps used for the stearic acid. Some paraffin wax should be put in a test tube and then
placed into a rack into a water bath at 75°C. Following this, a test tube rack should be on a
table and a thermometer should be placed into a test tube containing the paraffin wax. You
should then take out the test tube from the water bath and place it onto the test tube rack
onto the table. Measure the temperature of the paraffin wax; this is to ensure that it is at its
highest temperature before it starts decreasing. Then start a stopwatch. You then should
measure and record the temperature at 30 second intervals until the paraffin wax Is in a
, solid state or until the temperature stops decreasing. The last step is to place the test tube
back into the water bath and wait for it to melt, before removing the thermometer so that it
doesn’t break.
Results
Stearic Acid: Paraffin Wax:
Time Temperature
Time (seconds) Temperature (°C)
(seconds) (°C)
0 53
30 52 0 63
60 50 30 60
90 48 60 59
120 46 90 57
150 44
120 57
180 42
210 40 150 56
240 39 180 56
270 38 210 55
300 37 240 55
330 37
270 55
360 36
390 36 300 55
410 36 360 55
440 36 390 55
470 36
500 36
530 36
560 36
590 36
610 36
Section B- Keeping up with the standards
Practical for the cooling of stearic acid and paraffin wax
Method for the cooling of stearic acid and paraffin wax:
Apparatus required:
A test tube
Boiling tube
A water bath, which has been already set to 75 degrees Celsius.
A thermometer
Two test tube racks
Stearic Acid
Paraffin wax
Stopwatch
Stearic acid
Firstly, put stearic acid into a test tube and then place into a test tube rack into a water
bath, which has already been set to 75 degrees Celsius. Next, put a test tube onto a table
and put a thermometer in the test tube that contains the stearic acid. Then take the test
tube out of the water bath and place it into the test tube rack on the table. The next step is
to measure the temperature of the stearic acid; this is to ensure that the stearic acid is at its
highest temperature before its temperature starts to decrease. After you have done this,
start a stopwatch. You then need to measure and record the temperature for the
temperature of the stearic acid at 30 second intervals. Do this until the stearic acid appears
to be at a solid state, or until the temperature stops decreasing and remains stationary. The
last step involves placing the test tube back into the water bath and waiting for it to melt,
then removing the thermometer out of it afterwards, so that the thermometer doesn’t
shatter.
Paraffin Wax
The steps for the method used to investigate the cooling of paraffin wax is the same as the
steps used for the stearic acid. Some paraffin wax should be put in a test tube and then
placed into a rack into a water bath at 75°C. Following this, a test tube rack should be on a
table and a thermometer should be placed into a test tube containing the paraffin wax. You
should then take out the test tube from the water bath and place it onto the test tube rack
onto the table. Measure the temperature of the paraffin wax; this is to ensure that it is at its
highest temperature before it starts decreasing. Then start a stopwatch. You then should
measure and record the temperature at 30 second intervals until the paraffin wax Is in a
, solid state or until the temperature stops decreasing. The last step is to place the test tube
back into the water bath and wait for it to melt, before removing the thermometer so that it
doesn’t break.
Results
Stearic Acid: Paraffin Wax:
Time Temperature
Time (seconds) Temperature (°C)
(seconds) (°C)
0 53
30 52 0 63
60 50 30 60
90 48 60 59
120 46 90 57
150 44
120 57
180 42
210 40 150 56
240 39 180 56
270 38 210 55
300 37 240 55
330 37
270 55
360 36
390 36 300 55
410 36 360 55
440 36 390 55
470 36
500 36
530 36
560 36
590 36
610 36
