1. Which is true about spontaneous reactions?

Question

a. For a reaction to be spontaneous, Keq = 1.
b. Spontaneous reactions happen very rapidly.
c. A chemical reaction is spontaneous in both directions. ***
d. Spontaneous reactions do not require that anything be done to them.

2. At SATP, which reaction below is spontaneous?
a. CO2(s)→CO2(l)
b. CO2(s)→CO2(g) ***
c. CO2(g)→CO2(l)
d. CO2(l)→CO2(s)

3. For which system is ∆S<0?
a. CO2(g)→CO2(s) ***
b. CO2(s)→CO2(l)
c. CO2(s)→CO2(g)
d. CO2(l)→CO2(g)

4. Which pure substance under standard conditions would have the highest entropy?
a. H2O2(aq) ***
b. H2O(l)
c. H2O(s)
d. OH-(aq)

5. All the following involve a decrease in entropy except
a. condensation
b. crystallization
c. formation of a precipitate
d. diluting a weak base
***not sure about # 5.

Answer 1

I disagree with your choice for #1.
I think #5 is d. You increase "randomness" anytime you dilute something because there is more motion possible in a larger volume of solution.

Answer 2

1. would it be d, since spontaneous reactions occur naturally

Answer 3

I believe that is true.