CHEMISTRY COMMUNITY

In a perfect system, qsys + qsurr = 0. If a reaction is taking place inside a calorimeter, is qcalorimeter the equivalent of qsurr? Or is the calorimeter also part of the system?

It depends on the question because these allocations are relative. Generally, if we are measuring the heat of the reaction as the qsys, and we measure that as a change in temperature of the calorimeter, then qcalorimeter = qsurr because the calorimeter is acquiring the heat energy. However, we can also expand our perspective and look at the calorimeter as the system if we are measuring the change in temperature of the room in which we have placed the calorimeter. In that case, qcalorimeter = qsys and qroom = qsurr.