# Determine the standard molar entropy of formation?

Determine the standard molar entropy of formation at 298K for each of the following (recall what a formation reaction is from our discussion of heats of formation):

    Sfo J/mol-K

H2(g)

H2O(g)

NH3(g)

O3(g)

I2(g)

### 3 Answers

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• To get the entropy of formation you have to use your table of standard entropy, heat and energies.

H2(g) is zero

for H2O(g) you have to use the reaction H2(g)+(1/2)O2(g)--> H2O(g)

you take the standard entropy of products minus reactants and you get -44.385

for NH3(g) you use the reaction (1/2)N2(g) + (1/3) H2(g)--> NH3(g) you do the same as before take the entropy of products minus reactants and you end up with -99.3

for O3(g) you use the reaction (3/2)O2(g)-->O3(g) and you end up with -68.725

I can't figure out the last one sorry!!

RE:

Determine the standard molar entropy of formation?

Determine the standard molar entropy of formation at 298K for each of the following (recall what a formation reaction is from our discussion of heats of formation):

    Sfo J/mol-K

H2(g)

H2O(g)

NH3(g)

O3(g)   

I2(g)

• Standard Entropy Of Formation