1. The problem statement, all variables and given/known data A copper calorimeter with the heatcapacity of 75 J/K has 300 g of petrolium in it. The starttemp. is 17.8 C. A kobberweight of 100 g. is 100Celcius. It is being put in the petroleum, where the temperature ends up being 22 C. The specifik heatcapacity of coppe ris 387J(kg/K) What is petroleums specifik heat capacity? 2. Relevant equations C_pet*m_pet(t2-ts)+C_cop*m_cop(t2-t1)+C_cal*m_cal(t2-t1)=0 3. The attempt at a solution I think I have overlooked something - so I just need hints on the way. I don't have the mass of the calorimeter, but I now that it's heatcapacity is 75 J/K and I know that it's made of coper and the specifik heat capacity of that is 387 J(kg*K) If that is the way to go, then I have all the variables except the specifik heat capacity of petroleum, and then I just isolate C-Pet and it's piece of cake!