Standard electrode potentials

Question 1

what is the definition for a standard electrode potential

Answer 1

the voltage produced when a half cell is connected to a hydrogen half cell under standard conditions

Question 2

what are the standard conditions

Answer 2

298 K, 1 atm, 1 mol dm -3

Question 3

what is the electrochemical series

Answer 3

ranking metals and non metals by their standard electrode potentials - (oxidising ability and reducing ability)

Question 4

what are the charge carriers in the wire

Answer 4

electrons

Question 5

what are the charge carriers in the salt bridge

Answer 5

ions

Question 6

complete the sentance:
the more positive the standard electrode potential the stronger the ________

Answer 6

oxidising ability

Question 7

complete the sentance: the more negative the standard electrode potential the stronger the ______

Answer 7

reducing ability

Question 8

what is the definition for standard CELL potential

Answer 8

the voltage obtained when two half cells are connected under standard conditions

Question 9

what are the limitations of using SEP’s to predicr REDOX reactions

Answer 9

give no indication of the rate of reaction, reaction rate may be very slow, may be very high activation energy

majory of reactions will not occur under standard conditions so the actual electrode potential is likely to not be the same as the standard electrode potential

Question 10

is the reaction feasible if the Ecell sign is positive

Answer 10

yes

Question 11

is the reaction feasible if the Ecell sign is negative

Answer 11

no

Question 12

are primary storage cells rechargeable or non rechargeable
what kind of redox reaction is this

Answer 12

non rechargeable

non reversible

Question 13

are secondary storange cells rechargeable or non rechargeable. what kind of redox reaction is this

Answer 13

rechargeable

reversible

Question 14

during discharging which direction do electrons flow

Answer 14

most negative to least negative

Question 15

during charging, which direction do electrons flow

Answer 15

most positive to least positive

“flip most positive”

Question 16

many secondary storage cells are based on lithium-ion electrochemistry: what are the benefits of this?

Answer 16

• Lithium is a light metal giving a high energy density

-lithium ion cells are built around a solid polymer, means the cell can be formed into a wide range of shapes and sizes

Question 17

many secondary storage cells are based on lithium-ion electrochemistry: what are the limitations of this?

Answer 17

• voltage drops with use
• can be unstable at high temps
• lithium is very reactive so must take care when recycling.

Question 18

what are the 2 key features of fuel cells

Answer 18

• they have a continuous supply of fuel so do not have to be recharged.
• fuel and oxygen flow into the cell, products flow out.

Question 19

what is the benefit of hydrogen fuel cells

Answer 19

water is the only product ( however fossil fuels still needed to generate hydrogen in first place)