The combustion of 0.0222g of isooctane vapor, C8H18(g), at constant pressure raises the temperature of a calorimeter 0.400 C. The heat capacity of the calorimeter and water combined is 2.48 kJ/C. Find the molar heat of combustion of gasdeous isooctane.

Question

C8H18(g)+12 1/2O2(g) to 8CO2(g)+9H2O(l)
b. How many grams of C8H18(g) must be burned to obtain 495kJ of heat energy?

Answer 1

q = 2.48 kJ/C x 0.4C = ?? kJ.
??kJ/0.222 = ?kJ/g and
?kJ/g x (1 mole/molar mass) = kJ/mole.

Answer 2

51.10x10^3 kj/mol