The temperature rises from 25.00°C to 29.00°C in a bomb calorimeter when 3.50 g of sucrose undergoes combustion in a bomb calorimeter.Calculate ΔE_rxn for the combustion of sucrose in kJ/mol sucrose.The heat capacity of the calorimeter is 4.90 kJ/°C.The molar mass of sugar is 342.3 g/mol. A) -1.92 × 10³ kJ/mole B) 1.92 × 10³ kJ/mole C) -1.23 × 10³ kJ/mole D) 2.35 × 10⁴ kJ/mole

Question

Quizplus · Accepted Answer

First, we need to calculate the amount of heat released (q) by the combustion using the temperature change and the heat capacity of the calorimeter:

q = CΔT
q = 4.90 kJ/°C x (29.00°C - 25.00°C)
q = 19.6 kJ

Next, we need to convert the mass of sucrose combusted to moles:

moles of sucrose = 3.50 g / 342.3 g/mol
moles of sucrose = 0.0102 mol

Finally, we can calculate the standard enthalpy change of combustion (ΔH°) by dividing q by the number of moles of sucrose combusted:

ΔH° = q / moles of sucrose
ΔH° = 19.6 kJ / 0.0102 mol
ΔH° = 1922.2 J/mol
ΔH° = -1.92 kJ/mol

Since the question asks for the answer in kJ/mol, we need to convert J/mol to kJ/mol by dividing by 1000:

ΔH° = -1.92 kJ/mol

Therefore, the best choice is A, -1.92 × 10^3 kJ/mol.

The Temperature Rises from 25