posted by Fred on .
If you have the q cal of a reaction, then obviously you can convert to q chem by negating your q cal. But what if you need to get to q rxn (q of the reaction)? Also, my textbook is claiming that the q rxn = -(q sol + q cal). How does that figure into this?
I don't understand the question or your symbol meaning.
Question simplified: a) how do you get q of reaction if you have q of solution, b) how do you get q of reaction of you have q of calorimiter, c) how do you get q of solution if you have q of chemicals, d) in general, should q of chemicals equal q of solution, e) should q of calorimiter equal q of chemicals, f) should q of solution equal q of calorimiter?
I think you would do better to post a real, with numbers, instead of a general. In general, if one has q for the solution (I'm assuming something like a neutralization reaction), q reaction is q for the solution. Usually those problems ask for delta H/mol and you divide delta H by grams involved in the neutralization to obtain q/g or change to q/mol.
Usually q rxn + q calorimeter = heat input.
q for chemicals is
q = mass solvent x specific heat solvent x delta T.
I usually try to set them up so that
heat lost by one set + heat gained by another = 0.