Calorimetery Problem. It's not a homework but I can't get the answer.

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The discussion revolves around a calorimetry problem involving the combustion of ethanol. The user is calculating the change in enthalpy for burning 0.510 g of ethanol in a calorimeter containing 1200 g of water, which heats from 22.46 °C to 25.52 °C. The heat capacity of the calorimeter is given as 10.4 kJ/°C. The user attempts to use the equation Q(rxn) = Q(water) + Q(calorimeter) and expands it to calculate the heat released. They arrive at a value of 47.22 kJ but are unsure how to express this value per gram or per mole of ethanol. The discussion emphasizes the importance of correctly interpreting the sign of the enthalpy change and suggests that further clarification on relevant equations involving enthalpy and energy would be beneficial.
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Calorimetery Problem. :( It's not a homework but I can't get the answer.

0.510 g of ethanol is burned in a flame calorimeter (constant pressure) containing 1200 g of water. The water is initially 22.46 C and is warmed up to 25.52 C as a result of the reaction. The heat capacity of the calorimeter is 10.4 kJ/ C. What is the change in enthaply for the combustion of ethanol? Also, calculate the heat released when 73.5 g of ethanol undergoes combustion.
 
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Show an attempt at a solution? Relevant equations? Anything?
 


I did attempt it on my own. I was hoping someone would explain it to me though.


I used Q(rxn) = Q(water) + Q(calorimeter)

Also expanded: Q (rxn) = -[(m*s*change in temp.) + (C*change in temp.)]
= -[(1200*4.184*3.06) + (10400*3.06)] <---- I changed things from joules to kJ

And then I am lost from there. I got 47.22 KJ
 


Seems to me so far you are doing fine. 47.22kJ per how much ethanol? It will be better to list it either per gram or - even better - per mole. And watch the sign.

--
 


Your solution looks good so far, you're almost there. What equations do you know that include enthalpy and energy?
 

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