In: Chemistry
Determine the calorimeter heat capacity using the known enthalpy of combustion of benzoic acid.
Sample |
Tablet Weight(g) |
Initial Temp(K) |
Final Temp(K) |
Wirelength(cm) |
Wire left length(cm) |
Benzoic Acid |
0.99 |
294.35 |
296.75 |
9.3 |
0 |
Benzoic Acid(2) |
1.01 |
295.25 |
297.85 |
9.3 |
0.8 |
Naphthalene |
.98 |
294.95 |
298.75 |
9.3 |
1.0 |
Naphthalene(2) |
1.07 |
295.05 |
301.95 |
9.3 |
0.5 |
Determination of calorimeter heat capacity
moles of benzoic acid = 0.99 g/122 g/mol
= 0.008 mols
Enthalpy of combustion of benzoic acid = 3226 kJ/mol
So,
Heat released to calorimeter = 3226 kJ/mol x 0.008 mol
= 25.808 kJ
Heat capacity of calorimeter = 25.808/(296.75 - 294.35)
= 10.753 kJ/K