CHAPTER 19 TEST

Question 0

Laws of Thermodynamics:

Answer 0

2nd law- the universe constantly increases in disorder

3rd law- absolute entropy can be determined at only temperatures above 0K

Question 1

Spontaneous

Answer 1

Definite forming of products 
Does not define a time frame 
Disorder or different positions 
Represented by the letter S
Discovered by Ralph Clausius
In ***** J/K mol ******
Are the products or reactants thermodynamically favored?

Question 2

HOW TO PREDICT ENTROPY

Answer 2

Changes in state of matter: solid<gas
Forming solutions increases entropy
Pressure changes- entropy increases with LOWER PRESSURE bc lower pressure means more volume = more positions
Volume
Number of molecules- THE MORE THE MERRIER

Question 3

ENTROPY MUST BE….

Answer 3

POSITIVE TO FORM PRODUCTS

If - & - , then you must reverse the rxn!

Question 4

Exothermic

Answer 4

Surrounding entropy is positive

Question 5

Endothermic

Answer 5

Surrounding entropy is negative

Remember taxes

Question 6

Magnitude of entropy

Answer 6

Depends on the temp.; transferring heat into low temps. Produces a much greater change in disorder than at high temps

Question 7

Gibb’s free energy

Answer 7

HOW MUCH WORK DO YOU THINK ITS CAPABLE OF DOING?
Canberra used to show the direction that a reaction will proceed under any circumstance
Negative = spontaneous
Positive = not spontaneous
0= equilibrium ( unable to be seen) **phase changes

Question 8

Law of mass action

Answer 8

Gives us a relationship between the concentration of products and concentration of reactants *(K)
(Pressure of molarity of products)/(pressure of molarity of reactants)
K is Q if not at standard conditions
R= gas law constant= .0083145 kJ/mol K
K=1=Q EQUILIBRIUM
K>1>Q products are thermodynamically favored
K<Q reactants are favored

Question 9

Spontaneity with delta H and delta S

Answer 9

^ H ^S
- + = always spontaneous
+ + = spontaneous at high temps
- - = spontaneous at low temps.
+ - = never spontaneous