Question

Please help with part A and B

, 81% ' Sun 1:49 PM History Bookmarks Window Help < CHEM 1311 Ch 5 Problem 5.57 Part A Constants 1 Periodic Table What is the heat of combustion per gram of quinone? A 2.150 -g sample of quinone (C& H402) is burned in a bomb calorimeter whose total heat capacity is 7.854kJ/ C. The temperature of the calorimeter increases from 22.04 C to 29.01 C kJ/g Submit Previous Answers Request Answer Incorrect; Try Again; 5 attempts remaining Check your signs Part B What is the heat of combustion per mole of quinone? kJ/mol

Answer 1

Heat absorbed by the calorimeter:
dH = Cv dT
dH = (7.854kJ/C) (29.01 C - 22.04 C)
dH = 54.74 kJ (absorbed by the calorimeter)
dH reaction = - 54.74 kJ (released by the combustion)

heat of combustion per gram of quinone
(- 54.74 kJ) / (2.150 grams quinone) = - 25.46 kJ / gram burned

using its molar mass, heat of combustion per mole of quinone:
(- 25.46 kJ / gram) (108.095 grams per mol quinone) = - 2752.26 kJ/mol