Question

A 10.55 g sample of aniline (C₆H₅NH₂) was combusted in a bomb calorimeter with a heat capacity of 14.25 kJ/°C. If the temperature changes from 32.9°C to a final temperature of 45.4°C. What is the ΔH°rxn.

C₆H₅NH2(l) + 35O₂(g) → 24CO₂(g) + 14H₂O(g) + 4NO₂(g)

Answer 1

To find the standard enthalpy change (∆H°rxn) for the combustion of aniline, calculate the heat absorbed by the calorimeter (q = Ccalorimeter × ∆T) and adjust this value to a per mole basis by dividing by the number of moles of aniline.

Step-by-step explanation:

To calculate the ∆H°rxn for the combustion of aniline (C₆H₅NH₂) in a bomb calorimeter, we need to use the provided data from the experiment and apply concepts from thermochemistry. First, determine the amount of heat (q) absorbed by the calorimeter using the formula: q = Ccalorimeter × ∆T. The heat capacity (Ccalorimeter) is given as 14.25 kJ/°C, and the change in temperature (∆T) is the final temperature minus the initial temperature (45.4°C - 32.9°C).

Multiply these values to find q, which represents the heat released by the combustion of aniline. Since we are looking for ∆H°rxn per mole of aniline, convert the mass of aniline to moles using its molar mass, then divide q by the number of moles to find ∆H°rxn. Remember, since heat is released, ∆H°rxn should be negative, reflecting the exothermic nature of the combustion reaction.