Lecture notes all inclusive unit 3

Question 1

How far does the reaction proceed?

Answer 1

K value products are favored K>1

Question 2

How fast does the reaction proceed?

Answer 2

Value of k, when rate constant is large the reaction is fast

Question 3

Under what conditions will the reaction proceed?

Answer 3

Values of delta H, entropy and gibbs energy

Question 4

A chemical or a physical change that is thermodynamically favored by nature

Answer 4

Spontaneous process

Question 5

Spontanious process occur (with/without) continuous outside intervention

Answer 5

without

Question 6

Which process is NOT spontaneous at 25 ºC?
A. The melting of an ice cube.
B. The sublimation of dry ice, CO
2(s).
C. The boiling of liquid nitrogen.
D. The freezing of ethanol.

Answer 6

D.

Question 7

A thermodynamically spontaneous reaction (does not necessarily/ does) proceed at an observable rate

Answer 7

does not neccesarily

Question 8

Kinetics deals with reaction rates thermodyanimics deals with ______

Answer 8

spontaneity

Question 9

A spontaneous process is always non spontaneous in the _______

Answer 9

reverse direction

Question 10

Is it possible to reverse a spontaneous process?

Answer 10

-Sometimes. We need an input of energy

Question 11

Temperature affects spontaneity for ____ ____ ____ ___

Answer 11

Phase changes and such

Question 12

A T=0C for water which direction is spontaneous

Answer 12

neither

Question 13

A process that can be reversed by an infinitesimally small change in a variable

Answer 13

Reversible process

Question 14

What is reversed?

Answer 14

Both the system and its surroundings

Question 15

Whenever melting or a similar phase change is spontaneous

Answer 15

Irreversible process

Question 16

Reversing an irreversible process can only return the ____ to its original state, not the surroundings.

Answer 16

system

Question 17

For any ______ process, the process is _______ since the surroundings will have changed

Answer 17

spontaneous, irreversible

Question 18

Most spontaneous reactions are (endothermic/exothermic)

Answer 18

exothermic

Question 19

For an endothermic reaction to be spontaneous:

Answer 19

Delta S system and delta S surroundings > 0

Question 20

In an isolated system _____ ___ must be greater then zero while _____ _____ equals 0 always

Answer 20

Delta S system,

Delta S surroundings

Question 21

For a reversible process Delta SUniverse= Delta S system+ Delta S surroundings (=, >,

Answer 21

=

Question 22

For irreversible processes: Delta S universe= DeltaS system+ Delta S surroundings (, =)

Answer 22

>

Question 23

Entropy is a measurement of

Answer 23

Randomness

Question 24

Entropy is a _____ function

Answer 24

state So Delta S= Sfinal-Sinitial

Question 25

Delta S=

Answer 25

qrev/t

Question 26

qrev = ___ _ at constant pressue

Answer 26

Delta H (enthalpy)

Question 27

Gas does/ does not spontaneously compress

Answer 27

does not

Question 28

Very (equal/unequal) distributions become very impropable

Answer 28

unequal

Question 29

40C + 20 -> 30C

Answer 29

Spontaneous

Question 30

30c-> 40C + 20 C

Answer 30

not spontaneous

Question 31

It is more probable that energy will disperse over many particles than to be concentrated in a few

Answer 31

absorb dat

Question 32

Molecules can exhibit three different forms of motion:

Answer 32

translation, Rotation, Vibration

Question 33

Entropy is related to the W (distributions) of energy (microstates) among the energy levels of its molecules Boltzman formula=

Answer 33

S=k*ln(Wfinal/winitial)

Question 34

The molecules of a solid can only ____

Answer 34

Vibrate

Question 35

Liquid molecules can translate, rotate, and vibrate

Answer 35

absorb

Question 36

Gas molecules can also do these things and occupy a much larger volume

Answer 36

absorb

Question 37

Dissolving an ionic salt involves a disordering process (ions less confined) And and ordering process (some water molecules are more confined. Which of these process tend to dominate?

Answer 37

Disordering

Question 38

Generally, when a solid dissolved in a solvent, entropy _____

Answer 38

increases

Question 39

When w=1, the temperature is

Answer 39

0K

Question 40

The entropy of a pure crystalline substance at absolute 0 is _

Answer 40

0

Question 41

Entropy increases/decreases dramatically where?

Answer 41

At phase boundries

Question 42

(E/S) cant be measured but (E/S) can.

Answer 42

E | S

Question 43

Pure substances must have a positive S (0 doesnt count)

Answer 43

absorb

Question 44

Higher molar mass= (higher/lower) S

Answer 44

higher

Question 45

Delta S= Sproducts *coe - S reactants * coe

Answer 45

absorb

Question 46

-T(DeltaS univers)= DeltaH rxn -T(delta S rxn)

Answer 46

absorb

Question 47

At constant T & P: 1) If deltaG is negative, the forward reaction (is/ is not) spontaneous. 2) If deltaG is zero, the reaction (is/is not) at equilbrium. 3) If deltaG is positive, the forward reaction (is/is not) spontaneous, but the reverse reaction (is/is not) spontaneous.

Answer 47

is is is not is

Question 48

If using moles to calculatate *Delta G it is equal unit wise to __

Answer 48

kJ

Question 49

At temperatures not 25 C, *Delta G = Delta H-T(Delta S)

Answer 49

absorb

Question 50

Delta G is proportional to the ______ useful work that can be done by the system on the surroundings in a spontaneous process (p and T are constant)

Answer 50

Maximum

Question 51

negative delta Ge means a reaction is (spontaneous/ not spontaneous)?

Answer 51

spontaneous

Question 52

Delta H: - Delta S: + Delta G: -

Answer 52

Spontaneous at all temperatures

Question 53

Delta H: Positive Delta S: negative Delta G: positive

Answer 53

not spontaneous at any temperature

Question 54

Delta H: negative Delta S: negative Delta G: ?

Answer 54

spontaneous at low temp/ no at high temp

Question 55

Delta H: positive Delta S: postive Delta G: ?

Answer 55

no at low temp/ spontaneous at high temp