Question

Which Of The Following Would You Predict To Have A Positive Value For ΔSº
a.)AgCl(s) → Ag+(aq) + Cl-(aq)
b.)H2O(g) → H2O(l)
c.)2 Na(s) + Cl2(g) → 2NaCl(s)
d.)Br2(l) → Br2(s)

Answer 1

Please Help Me.

Answer 2

Any ideas? What do you currently know about \(\Delta S\)?

Answer 3

I Don't really know about that

Answer 4

I Think Its C

Answer 5

Well if you don't know about \(\Delta S\) at all... Then how do you expect to answer a conceptual question on it? #_#

Answer 6

Bond breaking is endothermic and bond forming is exothermic,
There's a relationship between entropy and heat enthalpy !
Entropy is directly proportional to negative enthalpy change.
\[\Delta S \alpha -\Delta H\]
So in order to Have a positive entropy the enthalpy change should be negative.
Usually enthalpy change is negative in exothermic reaction. Exothermic is when a bond is formed. So What do u think the answer is ?

Answer 7

Entropy is the amount of disorder in a system. So a positive change in entropy means you're going from ordered to disordered (since 0 entropy is perfect organization!)

Obvious ways to tell if entropy increased are:

Check if the number of moles of gas increased
The state changed from solid to liquid or from liquid to gas

These two facts are all you need to determine the answer!