Determine the water equivalent of the bomb calorimeter apparatus which gave the following data in an experiment: GCV of benzoic acid = 6324 cal/g Wt. of benzoic acid taken = 1.364 g Wt. of calorimeter = 1025 g Wt. of calorimeter + water = 3025 g Initial temperature = 11.872 C Final temperature = 14.625 C Cooling correction = 0.015 C Heat from fuses = 22 cals Washing of the bomb on analysis indicate the presence of 3.5 ml of N/10 HNO3 and there is no H2SO4formed.
Question
Determine the water equivalent of the bomb calorimeter apparatus which gave the following data in an experiment: GCV of benzoic acid = 6324 cal/g Wt. of benzoic acid taken = 1.364 g Wt. of calorimeter = 1025 g Wt. of calorimeter + water = 3025 g Initial temperature = 11.872 C Final temperature = 14.625 C Cooling correction = 0.015 C Heat from fuses = 22 cals Washing of the bomb on analysis indicate the presence of 3.5 ml of N/10 HNO3 and there is no H2SO4formed.
Solution
To determine the water equivalent of the bomb calorimeter apparatus, we need to calculate the total heat absorbed by the calorimeter and then divide it by the change in temperature.
Step 1: Calculate the heat produced by the combustion of benzoic acid. The heat produced (Q) is given by the formula Q = m * GCV, where m is the mass of the benzoic acid and GCV is the gross calorific value of the benzoic acid.
Q = 1.364 g * 6324 cal/g = 8627.536 cal
Step 2: Calculate the heat absorbed by the calorimeter. The heat absorbed by the calorimeter is the heat produced by the combustion of benzoic acid plus the heat from the fuses minus the heat absorbed by the HNO3 solution.
The heat absorbed by the HNO3 solution is given by the formula Q = m * C * ΔT, where m is the mass of the HNO3 solution, C is the specific heat capacity of the HNO3 solution, and ΔT is the change in temperature.
Assuming that the specific heat capacity of the HNO3 solution is approximately the same as that of water (1 cal/g°C), and that the density of the HNO3 solution is approximately the same as that of water (1 g/ml), the mass of the HNO3 solution is 3.5 g.
The change in temperature is the final temperature minus the initial temperature plus the cooling correction.
ΔT = 14.625°C - 11.872°C + 0.015°C = 2.768°C
Therefore, the heat absorbed by the HNO3 solution is
Q = 3.5 g * 1 cal/g°C * 2.768°C = 9.688 cal
The heat absorbed by the calorimeter is
Q = 8627.536 cal + 22 cal - 9.688 cal = 8639.848 cal
Step 3: Calculate the water equivalent of the calorimeter. The water equivalent (W) of the calorimeter is the heat absorbed by the calorimeter divided by the change in temperature.
W = Q / ΔT = 8639.848 cal / 2.768°C = 3123.5 g
Therefore, the water equivalent of the bomb calorimeter apparatus is 3123.5 g.
Similar Questions
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