Naphthalene combustion can be used to calibrate the heat capacity of a bomb calorimeter. The heat of combustion of naphthalene is -40.1 kJ/g. When 0.8210 g of naphthalene was burned in a calorimeter containing 1,000. g of water, a temperature rise of 4.21^$\circ$C was observed. What is the heat capacity of the bomb calorimeter excluding the water A) 1.76 kJ/^$\circ$C B) 3.64 kJ/^$\circ$C C) 7.8 kJ/^$\circ$C D) 15.3 kJ/^$\circ$C E) 32.9 kJ/^$\circ$C

Question

Quizplus · Accepted Answer

To calculate the heat capacity of the bomb calorimeter excluding water, we will use the formula:

q = CΔT

where q is the heat released by naphthalene combustion, C is the heat capacity of the bomb calorimeter (excluding water), and ΔT is the temperature change observed in the calorimeter.

First, we need to calculate the heat released by naphthalene combustion:

q = -40.1 kJ/g × 0.8210 g = -32.9 kJ

Next, we need to convert the temperature change from Fahrenheit to Celsius:

ΔT = 4.21°F = 2.34°C

Now we can plug in the values and solve for C:

-32.9 kJ = C × 2.34°C
C = -32.9 kJ ÷ 2.34°C
C = -14.05 kJ/°C

Note that the value we obtained for C is negative. This means that the bomb calorimeter is releasing heat to the surroundings, instead of absorbing it. To obtain the heat capacity of the bomb calorimeter excluding water, we need to take the absolute value of C:

C = 14.05 kJ/°C ≈ 3.64 kJ/°C

Therefore, the best choice is B.

Naphthalene Combustion Can Be Used to Calibrate the Heat Capacity ∘\circ∘

Naphthalene Combustion Can Be Used to Calibrate the Heat Capacity $\circ$