Calculate the heat capacity of a calorimeter if th ecombustion of 4.665 g of benzoic acid led to an increase in temperature of 7.148 C
im confused on how to get the grams to KJ.
Do you have the heat of combustion?
?kJ/mol x (4.665g/molar mass benzoic acid)
To calculate the heat capacity of a calorimeter, you need to use the equation:
q = m * C * ΔT
Where:
q = heat energy
m = mass
C = heat capacity
ΔT = change in temperature
In this specific case, we are given the mass of the benzoic acid (m = 4.665 g) and the change in temperature (ΔT = 7.148 °C). However, we need the value of heat energy (q) to find the heat capacity (C).
To find the heat energy, we need to know the enthalpy of combustion (ΔH) of benzoic acid, which is the amount of heat released when 1 mole of the substance undergoes combustion. The enthalpy of combustion for benzoic acid is -3226 kJ/mol.
To convert the given mass of benzoic acid to moles, we need to divide the mass by its molar mass. The molar mass of benzoic acid is approximately 122.12 g/mol. Therefore,
moles of benzoic acid = 4.665 g / 122.12 g/mol
Once we have the moles of benzoic acid, we can use the enthalpy of combustion to calculate the heat energy:
q = moles * ΔH
q = (4.665 g / 122.12 g/mol) * (-3226 kJ/mol)
Now, we need to convert the heat energy from kJ to J:
q = (4.665 g / 122.12 g/mol) * (-3226 kJ/mol) * (1000 J/1 kJ)
Finally, we can substitute the values of q, m, ΔT, and solve the equation for heat capacity (C):
q = m * C * ΔT
(4.665 g / 122.12 g/mol) * (-3226 kJ/mol) * (1000 J/1 kJ) = 4.665 g * C * 7.148 °C
Solving for C gives us:
C = [(4.665 g / 122.12 g/mol) * (-3226 kJ/mol) * (1000 J/1 kJ)] / (4.665 g * 7.148 °C)
Calculating this expression will give you the heat capacity of the calorimeter in J/°C.