Ch. 15

Question 1

Enthalpy (H)

Answer 1

heat or work added or removed from a substance

Question 2

entropy (S)

Answer 2

how dispersed a system’s energy is

Question 3

Important S trends

Answer 3

S of gas is greater than liquid is greater than solid
s increases with molar mass
s increases with molecular complexity
s increases with mobility of a phase
volume increase, entropy increase
temp increase, entropy increase

Question 4

Standard entropy S knot

Answer 4

absolute entropy of a substance at 1 atm. temp is not a par of standard state def. and must be specified.

Question 5

change of S system is equal to

Answer 5

n(1 mol)* R(8.314 j/k*mol)ln(Volume of final/ volume of initial in L)

Question 6

change in S knot is found by

Answer 6

sum of products - reactants

Question 7

What increases entropy

Answer 7

melting, vaporization, sublimation, temp. increase, increase in gas molecules, dissolving molecular compounds.

Question 8

change in S surrounding

Answer 8

calculated by -Hsys/T

Question 9

What does Suniverse need to be to be spontaneous?

Answer 9

positive

Question 10

change in G is equal to

Answer 10

change in H - change in Temp*S

Question 11

G, H, S sign table

Answer 11

G - + ? ?
H - + - +
S + - - +