Question

When 0.740g sample trinitrotoluene (TNT), C₇H₅N₂O₆, is burned in a bomb calorimeter, the temperature increases from 23.4˚C to 26.9˚C. The heat capacity of the calorimeter is 534J/˚C, and it contains 675ml of water. How much heat was produced by the combustion of TNT sample?

Short answer

The heat of the combustion for this reaction is 1.18 × 10⁴J.

Step-by-step solution

Given data

The mass of the TNT = 0.740 g

The increase in the temperature (∆T) = (26.9 – 23.4)˚C = 3.5˚C

The heat capacity of the calorimeter (C) = 534 J/˚C

Calculation of heat

The formula that is used in finding the heat of the combustion (q) in a bomb calorimeter is:

(q_bomb) = C × ∆T, where the symbols have their usual meaning. = 534 J/˚C × 3.5˚C

= 1869 J

The formula that is used in finding the heat from water is (q_water) = ms∆T, where the symbols have their usual meaning.

q_water = 675 g × 4.184 J/g℃ × 3.5℃

= 9884.7 J

Therefore, the heat of the reaction (q_reaction) = q_bomb+ q_water

= 9884.7 J + 1869 J

= 1.18 × 10⁴ J