5. Oxygen Bomb Calorimeter
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Transcript of 5. Oxygen Bomb Calorimeter
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5. OXYGEN BOMB CALORIMETER
(EXPERIMENT NO. 4)
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1. OBJECTIVES:
a) To know the different heats of combustion of
different organic compounds.
b) To know the different parts of a bomb calorimeter.
c) To be familiar with the standard procedure ofoperation of a bomb calorimeter.
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2. THEORY / HYPOTHESIS:
The heats evolved in the complete combustion of many
organic compounds in oxygen have been carefully
determined.
The method ordinarily used is to burn the substance in a
combustion bomb and to measure the heat volume, the
experimentally measured DE 's are converted and
corrected to DH.
The term heat combustion refers to the amount of heat
liberated per mole of substance burned.
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2. THEORY / HYPOTHESIS: (CONT..)
Heats of combustion may be employed directly to
calculate heats of formation of organic compounds.
If the organic compounds contain only carbon,
hydrogen, and oxygen, the supplementary information
required is the heats of formation of carbon dioxide and
liquid water, the usual final oxidation products of such
compounds.
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2. THEORY / HYPOTHESIS: (CONT..)
A bomb calorimeter is an instrument for measuring the
heat of combustion of a substance in which the heat
liberated when the sample is ignited in an atmosphere,
that is of oxygen under pressure, is measured. It is used
to obtain precise thermochemical data.
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2. THEORY / HYPOTHESIS: (CONT..)
The primary equipment used in this experiment is the
bomb calorimeter which is made up of a bomb where
the sample is ignited, the bucket where definite volume
of water is placed and the electronic system which
measures the heat of combustion of the substance
burned.
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3. LIST OF APPARATUS:
Oxygen Bomb Calorimeter
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3. LIST OF APPARATUS:
Oxygen Bomb Calorimeter
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4. SET-UP OF APPARATUS:
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5. PROCEDURE:
1) Pelletized about 0.5 to 1 g of sample using the
pelletizer and place it inside the sample holder.
2) Measure exactly 10 cm of the fuse wire. Lock it in
its place in the bomb electrode forming a loop at its
center and its tip touching the sample.
3) Place the cover of the bomb. Be sure to tighten its
cover.
4) Fill the bomb with oxygen by connecting the
oxygen hose and push the oxygen button.
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5. PROCEDURE: (CONT..)
5) Using the lifting handle, lower the bomb in the
water, push the two ignition lead wires into the terminal
sockets.
6) Lower the bomb completely into water with its feet
spanning the circular boss in the bottom of the bucket.
Carefully check for leak.
7) Press start. Input the sample ID, the bomb number
and weight of the sample.
8) Wait for the first beeping sound and move away
from the calorimeter.
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5. PROCEDURE: (CONT..)
9) At the second beeping sound, record the heat of
combustion and press done.
10) Open the cover and remove the bomb and the
bucket. Remove the knob from the bucket and open the
knurled valve. Knob as the bomb had to release the
residual pressure.
11) After all the pressure has been released, examine
for unburned fuse wire.
12) Straightened the wire and measure its length.
Convert this length calories and subtract this from the
reading obtained.12
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6. D ATA AND RESULTS:
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7. SAMPLE COMPUTATION:
8. QUESTIONS:
9. ANSWERS:
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10. DISCUSSION:
11. CONCLUSION / RECOMMENDATION:
12. REFERENCES:
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