Question

At constant volume, the heat of combustion of a particular compound, compound A, is -3530.0 kJ/mol. When 1.063 g of compound A (molar mass = 105.39g/mol) is burned in a bomb calorimeter, the temperature of the calorimeter (including its contents) rose by 6.477 degrees Celsius. What is the heat capacity (calorimeter constant) of the calorimeter?

Answer 1

To calculate the heat capacity of the bomb calorimeter, the heat released by burning 1.063 g of compound A with a known heat of combustion was used in conjunction with the observed temperature change. The final heat capacity (calorimeter constant) was determined to be 5.49 kJ/°C.

Step-by-step explanation:

To find the heat capacity (Ccalorimeter) of the bomb calorimeter, we can use the known heat of combustion and the temperature change that occurred when compound A was burned.

The amount of heat released can be calculated using the formula q = m × ΔH comb, where m is the mass of the substance burned, and ΔH comb is the heat of combustion per mole of the substance. For compound A, the heat of combustion is -3530.0 kJ/mol.

First, we need to determine the number of moles of compound A that was burned:

1. molar mass of A = 105.39 g/mol
2. mass of A burned = 1.063 g
3. Number of moles of A = mass of A / molar mass of A
4. = 1.063 g / 105.39 g/mol
5. = 0.01008 mol

Now, we can calculate the heat released during the combustion:

q = number of moles × heat of combustion per mole of A
= 0.01008 mol × (-3530.0 kJ/mol)

= -35.56 kJ

The heat capacity of the calorimeter can be determined using the formula q = Ccalorimeter × ΔT, where ΔT is the change in temperature of the calorimeter.

Ccalorimeter = q / ΔT
= -35.56 kJ / 6.477 °C
= -5.49 kJ/°C

Therefore, the heat capacity (calorimeter constant) of the bomb calorimeter is 5.49 kJ/°C.