chemistry

For the following reactions is delta Hrnx equal to delta Hf of the products :

a. CaCO3(g)----> CaO + CO2(g)
b. 2Na(s)+ Cl2(g) ---> 2NaCl(s)
c. C(s)+ O2(g) -----> CO2(g)
d. CO(g)+ 1/2O2(g)---> CO2(g)
e. Na(s)+ 1/2Cl2(l) ---> NaCl(s)
f. Na(s)+ 1/2Cl2(s) ---> NaCl(s)

i Know that A and D are not since they are compounds, I cant seem to get the answer, because i cant really distinguish between the rest.

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asked by Sara
  1. By the definition of heat of formation (when one mole of compound is formed from the elements at 25C), the only possible equations is c. For f) I have never seen chlorine as a solid.

  2. oops its Cl (g)

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    posted by Sara
  3. The f is from the elements, yielding one mole.

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