At constant volume, the heat of combustion of a particular compound is –3599.0 kJ/mol. When 1.365 g of this compound (molar mass = 102.90 g/mol) was burned in a bomb calorimeter, the temperature of the calorimeter (including its contents) rose by 7.819 °C. What is the heat capacity (calorimeter constant) of the calorimeter?
molescompound*Heatcombutstion=Heatcapacity*deltaTemp
1.365/102.90 * 3599.0 =7.819*Heatcapcity
solve for heat capacity. Pay attention to units.
To find the heat capacity (calorimeter constant) of the calorimeter, we need to use the equation:
q = C * ΔT
where:
- q is the heat released or absorbed by the system,
- C is the heat capacity of the calorimeter,
- ΔT is the change in temperature.
In this case, the heat released by the combustion of the compound is given as -3599.0 kJ/mol, and the temperature change is 7.819 °C.
First, let's calculate the heat released by the burning of 1.365 g of the compound. We can use the molar mass of the compound to convert grams to moles:
moles of compound = mass (g) / molar mass (g/mol)
moles of compound = 1.365 g / 102.90 g/mol ≈ 0.01327 mol
Now, let's calculate the heat released for the given amount of compound:
heat released = q = heat of combustion * moles of compound
heat released = -3599.0 kJ/mol * 0.01327 mol ≈ -47.75473 kJ
Next, we can substitute the values into the equation and solve for the heat capacity (C):
-47.75473 kJ = C * 7.819 °C
Now, rearrange the equation to solve for C:
C = -47.75473 kJ / 7.819 °C ≈ -6.1161 kJ/°C
Therefore, the heat capacity (calorimeter constant) of the calorimeter is approximately -6.1161 kJ/°C.