Which of the following are true statments?

Question

a) For the reaction CO2(g) → CO2(s)
entropy increases


b) For the reaction NaCl(s) + H2O(l) → NaCl(aq)
entropy increases


c) Molecules Cl2(g) should have have greater
entropy per mole, than molecules of SO2(g)


d) If entropy decreases for a certain process, the entropy of the universe increases

Answer 1

a) False
b) True
c) False
d) True

Answer 2

You need to just think about this a bit, and you'll be able to answer it yourself. Entropy is a measure of the number of possible arrangements of the particles in a system. So, in a solid, each particle is in a locked fixed position. In a liquid, the particles are free to move around within the liquid. In a gas (which has the highest entropy), there are many more places you can put any individual molecule.

The entropy of assymetric molecules will be higher than symmetrical ones.

For the last one, think about the second law of thermodynamics, and think about some specific examples of changes which involve a decrease in the entropy of the system (for example, water freezing, or a precipitation reaction).