Copyright ©
Houghton Mifflin Company. All rights reserved.
CRS Question, 6–29
QUESTION
The following reaction shows
one method to obtain phosphoric acid from phosphate containing
rock:
If
the heat of formation of Ca3(PO4)2 (s) was unavailable, but the heat
of reaction was known to be -265 kJ for the reaction of one mole
of Ca3(PO4)2 and the enthalpy changes for the rest of the reactants
and products were known, how would you determine the heat
of formation for Ca3(PO4)2 (s)?
Ca3(PO4)2 (s) + 3 H2SO4 (l) ® 3 CaSO4 (s) + 2 H3PO4 (l)