Bomb Calorimeter Essay

Experiment B2, Heats of Combustion – The Bomb Calorimeter.

Objectives:

To calibrate a bomb calorimeter by the combustion of benzoic acid. Then to use the calibrated calorimeter to measure the heat of combustion of naphthalene and calculate the heat of formation of naphthalene.

Theory:

q = C.ΔTBA C = q / ΔTBA

Moles = mass / Mr

ΔŪ = ΔU / moles

ΔHoc,298 = ΔŪoc,298 + PDV = ΔŪoc,298 + RTΔn

C10H8 (s) + 12O2 (g) 10CO2 (g) + 4H2O (l)

ΔHoc,298 = - 1 x ΔHof (Nap) + 10 x ΔHof (CO2) + 4 x ΔHof (H2O)

Procedure:

1. First, a pellet of approximately 1.0g of benzoic acid was weighed out using a four decimal place mass balance and the weight was recorded at 1.0022g recorded.
|2.0 |21.0 |22.7 |
|2.5 |21.1 |22.7 |
|3.0 |21.1 |22.7 |
|3.5 |21.0 |22.7 |
|4.0 |21.1 |22.7 |
|4.5 |21.1 |22.7 |
|5.0 Bomb Fired |21.1 |22.7 |
|5.5 |21.5 |23.2