Experiment #6 – Calorimetry
Calorimetry is the science of measuring heat.
Purpose: Measure the heat exchange in various processes.
q = heat = mCΔT
m = mass of system
C = heat capacity
ΔT = change in temperature = T T f i
q = ΔH (when ΔP = 0) (enthalpy)
MB (s)eat ▯M (aq)+ B (aq)
heat gained by salt = heat lost by solution + heat lost by calorimeter
qsystem= (qsolutionq calorimeter
ΔH = m C ΔT – C ΔT
system solutiosolution calorimeter
ΔH = ΔH systemnsystem
Rearranging and substituting…
ΔH = ((M systemT)/m system[(4.18)V solution calorimeter
M system molecular weight of salt
ΔT = T fT i
m system mass of salt
4.18 = heat capacity of solution = C solution
V solution volume of solution
C calorimetercalorimeter constant
I. Determining C calorimeter
1) Measure ~50 mL of water. Record the exact volume.
2) Pour water into the calorimeter. Cover with the lid.
3) Record the temperature every 30 seconds until stable.
a. stable temperature = T = T
cold water, initCW, i
4) Boil around 120 mL of water.
a. can mess up if boil water too early or too long
b. need 100120 mL of boiling water o
5) Assume the temperature of the hot water is 100 C
6) Transfer the boiling water to the calorimeter using heavy gloves (should still
have cold water in it).
7) Cover the calorimeter and agitate it. 8) Record temperature every 30 seconds for 5 minutes agitating throughout.
(Don’t record time at 0 s