Finding the Molar Enthalpy of a Reaction with One Solid Product and One Gaseous Product
December 11, 2011 4:35 PM Subscribe
This is a hypothetical chemistry question. I'm tutoring someone, and a question like this came up on their exam. There was no answer provided, so I don't know if the answer we found was correct.
posted by mondotwistedmojo to science & nature (7 answers total) 3 users marked this as a favorite
Say you have some reaction that (when the limiting reactant has been exhausted) produces 2.5 moles of some solid and 5.2 moles of a gas. You find that the heat released by this reaction is 32.3 kJ.
How do you find the molar enthalpy of reaction? "Molar enthalpy" usually implies that you are finding the enthalpy per each mole of product that is produced- but what is the procedure with two separate products? Do you divide the heat produced by the moles of the gas, by the moles of the solid, or by the combined moles of both?
I have seen problems in which there was one solid product and one aqueous product; in that case, the aqueous product is ignored and the heat produced is divided by the moles of the solid precipitate. I don't think that the above case is the same as that.