Posted by **marcus** on Wednesday, November 14, 2012 at 9:24pm.

consider the following changes at constant temperature & pressure

H2O(s) --yields-- H20(l); Delta H1

H2O(l) --yields-- H2O(g); Delta H2

H2O(g) --yields-- H2O(s); Delta H3

Using Hess's law, the sum of the deltas is

a. equal to 0

b. sometimes greater than zero, sometimes less than zero

c. less than 0

d. cannot be determined without the numerical values of delta H

e. greater than 0

I picked e because delta 1 looks to be an endothermic reaction, delta 2 also endothermic, and delta 3 is exothermic reaction. But the answer is equal to 0. Why?

## Answer This Question

## Related Questions

- Chemistry - Consider the following data: * NH3(g) yields 1/2 N2(g) + 3/2 H2(g) ...
- Chemistry - Mg + 2HCl -> MgCl2 +H2 delta H = ? MgO + 2HCl (aq) -> MgCl2+ ...
- Chemistry - Calculate the enthalpy of the reaction 2B2H6 + 6O2=2B2O3 +6H2O given...
- chem - given the thermochemical equations, B2O3 + 3H2O -> 3O2 + B2H6 delta h...
- Chem - RXN #1: H2 (g) + O2 (g) --> H2O2 (l) ; delta-H =? Calculate the ...
- Chemistry - H2O (liquid) yields H2O gas delta H= +44kJ. How much heat is evolved...
- Chemistry - Calculate the work involved if a reaction with an enthalpy change of...
- Chemistry - I am having trouble with this equation and calculating the enthalpy ...
- Chemistry - Consider the following three reactions: Ca(s) + 2H2O(l) ---> Ca2...
- Chemistry - Please help me N2O5(g) + H2O(l) --> 2HNO3(l) delta HÂ° = -76.2 kJ ...

More Related Questions