The combustion of 1.881 g of glucose, C 6 H 12 O 6 ( s ) , in a bomb calorimeter with a heat capacity of 4.90 kJ/°C results in an increase in the temperature of the calorimeter and its contents from 22.06 °C to 28.04 °C. What is the internal energy change, Δ U , for the combustion of 1.881 g of glucose?

2804.02 kJ/mol.

Explanation:

Equation of reaction:

C6H12O6 + 6O2 --> 6CO2(g) + 6H2O(g)

Molar mass of C6H12O6 = (6*12) + (12*1) + (6*16)

= 180 g/mol

Number of moles = mass/molar mass

= 1.881/180

= 0.01045 mol.

ΔU = q + W

W = 0,

ΔU = q

ΔT = 28.04 - 22.06

= 5.98 °C

qrxn = qcal;

qcal = Ccal * ΔT

= 4.9 * 5.98

= 29.302 kJ

ΔU = qcal/n

= 29.302/0.01045

= 2804.02 kJ/mol.