Entropy Video Lessons

Concept

# Problem: Rank the following substances in order of decreasing standard molar entropy (S˚).a. I2(g); F2(g); Br2(g); Cl2(g)b. H2O(g); H2O2(g); H2S(g)c. C(s, graphite); C(s, diamond); C(s, amorphous)

###### FREE Expert Solution

1. Phase: The gas phase has the highest entropy, followed by the liquid, and then the solid phase with the lowest entropy.

Gas > Liquid > Solid

2. Complexity: More elements in the compound leads to higher entropy.

Ex. NO3(g) [4 elements] has higher entropy than NO2(g) [3 elements].

3. Mass: The greater the mass, then the greater the entropy.

Ex. Xe(g) [greater mass] has higher entropy than He(g).

a. I2(g); F2(g); Br2(g); Cl2(g)

molar masses:

I2(g) = 253.8 g/mol
F2(g) = 38.0 g/mol
Br2(g) = 159.8 g/mol
Cl2(g) = 70.9 g/mol

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###### Problem Details

Rank the following substances in order of decreasing standard molar entropy (S˚).
a. I2(g); F2(g); Br2(g); Cl2(g)
b. H2O(g); H2O2(g); H2S(g)
c. C(s, graphite); C(s, diamond); C(s, amorphous)