help with chemistry please?

Question

Predict the signs of spontaneous change for each of the following processes. (+ or -)?

a.) A piece of wax melting
b.) silver chloride precipitating from a solution
c.) Dew forming
d.) gasoline vapors mixing with air in a car engine
e.) hot air expanding
f.) breath condensing in cold air

Answer 1

When matter changes from a more ordered state(lower entropy) to a more disordered state(higher entropy), the total entropy would increase leading to a + sign for the change in entropy which means the reaction is spontaneous. Similarly, - sign shows a decrease in entropy and the reaction is non-spontaneous.

a) + because matter changes from a more ordered state to a more disordered state

b) - (AgCl becomes more ordered hence entropy decreases)

c) -

d) +

e) +

f) -

Answer 2

Only b.) is a chemical change. All the others are physical changes.

Answer 3

a)-
b)-
c)+
d)+
e)+
f)-

Hope it helps not sure about d.