PhyChem 2 Midterm Exam

Question 1

Mixtures for which the solute obeys Henry’s law and the solvent obeys Raoult’s law are called ___________________.

Answer 1

ideal-dilute solutions

Question 2

The ratio of the partial vapour
pressure of each component to its vapour pressure as a pure liquid, pA/p*A, is approximately equal to the mole fraction of A in the liquid mixture.

Answer 2

Raoult’s law

Question 3

for real solutions at low concentrations, although the vapour pressure of the solute is proportional to its mole fraction, the constant of proportionality is not the vapour pressure of the pure substance.

Answer 3

Henry’s Law

Question 4

A ________________ depends only on the number of solute particles present, not
their identity.

Answer 4

colligative property

Question 5

Enumerate the colligative properties.

Answer 5

(a) elevation of boiling point
(b) depression of the freezing point
(c) solubility
(d) osmosis

Question 6

(from the Greek word for ‘push’) is the spontaneous passage of a pure solvent into a solution separated from it by a semipermeable membrane

Answer 6

osmosis

Question 7

The _____________ theory ascribes deviations from ideality to the Coulombic interaction of an ion with the ionic atmosphere that assembles around it.

Answer 7

Debye–Hückel

Question 8

delta G<0, (exergonic) the forward reaction is

Answer 8

spontaneous

Question 9

delta G>0, (endergonic) reverse reaction is

Answer 9

spontaneous

Question 10

delta G=0, reaction is

Answer 10

equilibrium

Question 11

A system at equilibrium, when subjected to a disturbance, responds in a way that tends to minimize the effect of the disturbance

Answer 11

Le Chatelier’s principle

Question 12

__________________ is an expression for the slope of a plot of the equilibrium constant (specifically, ln K) as a function of
temperature

Answer 12

van’t Hoff equation

Question 12

E* is also known as the ______________.

Answer 12

standard electrode potential

Question 13

Oxidation is ________ of electrons.

Answer 13

loss

Question 14

Reduction is ________ of electrons.

Answer 14

gain

Question 15

Oxidation and reduction occur __________.

Answer 15

simultaneously

Question 16

Oxidation results in an ________ in oxidation number.

Answer 16

increase

Question 17

Reduction results in an ________in oxidation number.

Answer 17

decrease

Question 18

Zn to Zn+2 is ____________ because___________.

Answer 18

oxidation because the O.N increases from 0 to +2

Question 19

H+ to H is ____________ because_________________.

Answer 19

reduction because the O.N decreases from +1 to 0.

Question 20

If delta G<0 then the reaction is ___________.

Answer 20

spontaneous

Question 21

a _________________ uses a spontaneous redox reaction to generate electrical energy.

Answer 21

voltaic cell

Question 22

a ________________ uses electrical energy to drive a nonspontaneous reaction.

Answer 22

electrolytic cell

Question 23

delta G>0 then the reaction is _________.

Answer 23

nonspontaneous

Question 24

Electrochemical cells are constructed using 2 main components ____________ and ____________ solution.

Answer 24

electrolyte and electrode

Question 25

The electrode at which oxidation occurs.

Answer 25

anode

Question 26

The electrode at which reduction occurs.

Answer 26

cathode

Question 27

It is a cell where energy is released from a spontaneous redox reaction.

Answer 27

voltaic cell

Question 28

It is a cell where energy is absorbed to drive a nonspontaneous redox reaction.

Answer 28

electrolytic cell

Question 29

electrons flow from __________ to ______________.

Answer 29

anode to cathode

Question 30

half cells are connected by the external circuit that is called ___________.

Answer 30

salt bridge

Question 31

Anode is the __________ electrode in a voltaic cell.

Answer 31

negative

Question 32

Cathode is the __________ electrode in a voltaic cell.

Answer 32

positive

Question 33

Salt bridge allows ________ to flow through both half cells.

Answer 33

ions

Question 34

The salt bridge maintains ___________ __________ by allowing excess Zn2+ ions to enter from the anode, and excess negative ions enter from the cathode.

Answer 34

electrical neutrality

Question 35

A salt bridge contains ____________ cations and anions often K+ and NO3-; dissolved in a gel.

Answer 35

nonreacting

Question 36

_____________ electrode is a component in its half cell and is a reactant or product in the overall reaction.

Answer 36

active

Question 37

_____________ electrode provides a surface for the reaction and completes the circuit. It does not participate actively in the overall reaction.

Answer 37

inactive

Question 38

Name 2 examples of common inactive electrodes.

Answer 38

Platinum and graphite

Question 39

Anode components are written on the _________________.

Answer 39

left

Question 40

Cathode components are written on the _________________.

Answer 40

right

Question 41

double line in a cell notation means ____________.

Answer 41

half cells are physically separated.

Question 42

the single line shows a _________ between the components of a half cell.

Answer 42

phase boundary

Question 43

a comma is used to show that _____________.

Answer 43

components are in the same phase.

Question 44

It depends on the difference in electrical potential between the two electrodes.

Answer 44

cell potential

Question 45

the cell potential is also known as the _______________ or ____________________.

Answer 45

voltage of the cell or the electromotive forces (emf)

Question 46

The ______________ is designated Ecell and is measured at a specific temperature with no current flowing and all components in their standard states.

Answer 46

Standard Cell Potential

Question 47

Ecell is equal to (write the formula)

Answer 47

Ecell= cathode minus anode

Question 48

___________________ has a standard electrode potential defined as 0.

Answer 48

Standard Hydrogen Electrode

Question 49

potential rises due to a chemical reaction occurring in the cell

Answer 49

Chemical cell

Question 50

potential rises due to a concentration difference, resulting in transfer of matter.

Answer 50

Concentration cell