Question

Constant-volume calorimeters are sometimes calibrated by running a combustion reaction of known ΔE and measuring the change in temperature. For example, the combustion energy of glucose is 15.57 kJ/g. When a 2.000 g sample of glucose burns in a constant volume calorimeter, the calorimeter temperature increases from 21.45 to 23.34°C. Find the total heat capacity of the calorimeter (in kJ/K).

Answer 1

Answer:

0.1132 kJ/K the total heat capacity of the calorimeter.

Explanation:

The combustion energy of glucose = 15.57 kJ/g.

Energy released on 2 combustion of 2.000 g of glucose = Q

$Q= 15.57 kJ/g\times 2.000 g=31.140 kJ$

Q=31.140 kJ

Heat gained by the calorimeter = Q'

Heat gained by the calorimeter = heat released on combustion of glucose

Q'= 31.140 kJ

Temperature change of the calorimeter = ΔT = 23.34°C - 21.45°C = 1.89°C

ΔT = 1.89°C = 275.04 K

Total heat capacity of the calorimeter = C

$Q'=C\times \Delta T$

$C=\frac{Q'}{\Delta T}=\frac{31.140 kJ }{275.04 K}=0.1132 kJ/K$

0.1132 kJ/K the total heat capacity of the calorimeter.