The enthalpy of combustion of benzoic acid

(C6H5COOH) which is often used to calibrate
calorimeters, is −3227 kJ/mol. When 1.402 g
of benzoic acid was burned in a calorimeter,
the temperature increased by 3.401

C. What
is the overall heat capacity of the calorimeter? The overall heat capacity includes the
calorimeter hardware and the water that is in
it.
Answer in units of kJ/

C

I answered that for you almost an hour ago.

To find the overall heat capacity of the calorimeter, we need to use the equation:

q = m × C × ΔT,

where:
q is the heat transferred,
m is the mass of the substance being heated (in this case, the water),
C is the specific heat capacity of the substance (in this case, the overall heat capacity of the calorimeter),
ΔT is the change in temperature.

In this case, we know the mass of benzoic acid burned (1.402 g), the change in temperature (3.401 degrees Celsius), and the enthalpy of combustion of benzoic acid (-3227 kJ/mol).

First, we need to find the number of moles of benzoic acid burned using its molar mass.

The molar mass of benzoic acid (C6H5COOH) can be calculated as follows:
6 carbon atoms (6 × 12.01 g/mol) + 5 hydrogen atoms (5 × 1.008 g/mol) + 2 oxygen atoms (2 × 16.00 g/mol) + 1 oxygen atom (16.00 g/mol) + 1 hydrogen atom (1.008 g/mol)
= 122.13 g/mol.

The number of moles of benzoic acid burned is therefore:
moles = mass / molar mass
= 1.402 g / 122.13 g/mol.

Next, we need to calculate the heat transferred (q) during the combustion of benzoic acid. Since the heat transferred equals the enthalpy of combustion multiplied by the number of moles, we can use the equation:

q = enthalpy of combustion × moles.

Substituting the given values:
q = (-3227 kJ/mol) × (1.402 g / 122.13 g/mol).

Now, we can use the equation for heat transfer to find the overall heat capacity (C) of the calorimeter. We rearrange the equation for q:

q = m × C × ΔT.

Solving for C:

C = q / (m × ΔT).

Substituting the known values:
C = (-3227 kJ/mol × (1.402 g / 122.13 g/mol)) / (1.402 g × 3.401 °C).

Now, we can calculate the overall heat capacity of the calorimeter by plugging in the values and calculating the result.