Question

Here is the question:

A sample of ethanol, C2H5OH, weighing 2.84g was burned in an excess of oxygen in a bomb calorimeter. THe temperature of the calorimeter rose from 24C to 33.73C. If the heat capacity of the calorimeter and contents was 9.63 kj/C. What is the calue of q for burnign 1 mol of ethanol at constant volume and 25.00C?

C2H5OH(l)+3O2(g)-->2CO2(g)+3H2O(l)

Here is my Homework:

q=ms(T final - T initial)

q=2.84x9.63kj/C x (33.73C-25C)= 238.76

But 238.76 is not the correct answer, the book states that it is -00136kJ

Can anyone tell me what I am doing incorrect?

Answer 1

You figured the q for 2.84g. Now figure it for a mole of ethanol.

Use a proportion.

Answer 2

2.48/46.068g/mol ethanol=.06165

.06165x9.63kj/C x (33.73C-25C)= 5.183 ??

still not the -00136kJ I am looking for??