the part or title of the experiment is determinat of molar heat of reaction of a precipitat reaction

Question

when performing an experiment to determine the molar heat of a reaction, a student spilled three fourth of the Fe(NO3)3 solution on the lab bench. The student used the remaining fourth to complete the experiment. Will the heat of reaction determined experimentally be lower or higher than it would have been if all the Fe(NO3)3 solution had been used. Justify your answer with an explanation.  What will happen if the student doesn't record the amount of solution left after the spillage and instead does her calculations with the values of the original amount of Fe(NO3)3. 

Answer 1

The molar heat of reaction is a per-unit quantity, meaning it is a measure of how much heat is absorbed per mole of reactant.  So, as long as the student accurately determines how many moles of reactant there are after spilling, and then determines the heat absorbed, the student should get the same value for heat absorbed per mole of reactant.

 

If there had been no spillage, there would have been more moles of reactant, but also more heat absorbed to do the reaction.  After spillage, there is a smaller number of moles, but also correspondingly less heat will be absorbed.  The proportion of heat absorbed per mole of reactant will remain the same.