Experiment V

Question 1

mnemonic to remember electrochemistry electron rules

Answer 1

LEO is a GERC

Question 2

spontaneous reaction

Answer 2

SOA and SRA are on the left side of the equation

Question 3

non-spont. reaction

Answer 3

SOA and SRA are on the left side of the equation

Question 4

reduced form of a half reaction

Answer 4

(electron on left side)
Ag+ + e- = Ag

Question 5

oxidized form of a half reaction

Answer 5

electron on right side
Ag = Ag+ + e-

Question 6

galvanic/voltaic cell

Answer 6

cell in which current is generated from spontaneous reactions

Question 7

Electrons flow in what direction

Answer 7

negative to positive

Question 8

salt bridge

Answer 8

allows for ion exchange but not wholesale mixing

Question 9

cell voltage

Answer 9

measure of the driving force or the degree of spontaneity of the reaction

Question 10

Halogen reaction general form

Answer 10

X2 + 2e- = 2X-

Question 11

how does can halogens inform us about the spontaneity of reactions

Answer 11

Halogen are highly soluble in Hexane, but not water. (like dissolves like)

Ions are highly soluble in water but not hexane.

If hexane changes colour, it means that there is I2 present in it and thus the reaction proceeded

If it does not change colour, it means that there is still only I- present and thus the reaction did not proceed

Question 12

Ecell of a spontaneous reaction

Answer 12

positive

Question 13

Ecell of a non spontaneous reaction

Answer 13

negative

Question 14

What colour would iodine change the colour of hexane to

Answer 14

reddish purple - purple

Question 15

What colour would chloring change the colour of hexane to

Answer 15

light yellow

Question 16

voltage

Answer 16

difference between the E° of half cells

Question 17

E°

Answer 17

concentration of dissolved species = 1M
pressure of gases = 1M

Question 18

if you have a non-standard cell, what do you use

Answer 18

use Nernst equation

Question 19

how is E° cell affected by multiplying half-cell by integer

Answer 19

it is not, it is an intensive property and thus unaffeced

Question 20

How should you look at the data table if you want to make a spontaneous cell

Answer 20

you need a positive final number, so take the cathode below the anode

Question 21

greater positive E

Answer 21

cathode

Question 22

greater negative E

Answer 22

anode

Question 23

Lab V part 3 reaction of precipitate

Answer 23

2Ag+ + S2O3^2- = (Ag2)S2O3

and then

(Ag2)S2O3 decomposes into Ag2S

Question 24

what colour is (Ag2)S2O3

Answer 24

white/cream precipitate

Question 25

what colour is Ag2S

Answer 25

black precipitate

Question 26

ICE table rules for 2Ag+ + S2O3^2

Answer 26

If ppt forms, reaction goes to 100% If no ppt forms, ICE table has a stoich shift, then a small change to equilibrium

Question 27

what colour is Ag(S2O3)2^3-

Answer 27

colourless and clear. not a precipitate

Question 28

cell shorthand for a cell that produces precipitate

Answer 28

Ag(s) | Ag+(? M) ∥ Ag+(1 M) | Ag(s)

Question 29

Why is the Ag+(?M) the anode

Answer 29

Because Ag+ is the concentration of of ions after the formation of the complex ion, thus there is a lower concentration of them in the solution This means the Ag electrode will oxidized, so that Ag+ concentration increases The extra e- formed during the oxidation, travels to the cathode

Question 29

Why is the Ag+(?M) the anode, when forming

Answer 29

Because the Ag+ is the concentration of ions after precipitating, there is a lower concentration in the solution. That means the Ag electrode will be oxidized, so that Ag+ concentration increases. The extra e- formed during the oxidation, travel to the cathode