6772
Calorimetric Thermometer Instruction Manual
4-6
Remove all unburned pieces of fuse wire from the bomb electrodes; straighten them and
measure their combined length in centimeters. Subtract this length from the initial length of
10 centimeters and multiply this burned length by 2.3 calories per cm (for Parr 45C10 Fuse
Wire) to obtain the fuse correction. The scale on the fuse wire card can be used to obtain this
value directly.
Titrate the bomb washings with a standard sodium carbonate solution using methyl orange,
red or purple indicator. A 0.0709N sodium carbonate solution is recommended for this
titration to simplify the calculation. This is prepared by dissolving 3.76 grams of Na
2
CO
3
in
the water and diluting to one liter. NaOH or KOH solutions of the same normality may be
used.
Analyze the bomb washings to determine the sulfur content of the sample if it exceeds
0.1%. Methods for determining sulfur are discussed in Operating Instructions No. 207M.
