redox

Question 1

oxidation - define

Answer 1

loss of electrons
gain of O2
loss of H2
increase in oxi number

Question 2

reduction - define

Answer 2

gain of electrons
loss of O2
gain of H2
decrease in oxi number

Question 3

oxidising agent

Answer 3

readily accept electrons, and substance that is reduced

Question 4

activity series

Answer 4

higher up = stronger reducing agent/oxident and more reactive
lower = weaker reducing agent/reductant

Question 5

in voltaic cell: anode = and cathode =

Answer 5

anode = -ve electrode and its oxidising
cathode = + electrode and its reducing

Question 6

electrolytic cell: anode = and cathode =

Answer 6

anode = +ve electrode and its oxidising
cathode = -ve electrode and its reducing

Question 7

rules for oxi numbers

Answer 7

1. ionic compound - each element takes its charge
2. covalent compound - more electronegative takes negative change as if ionic
3. sum of all oxi numbers in compound = 0
4. sum of all oxi numbers in ion = charge on ion
   elements have an oxi number of 0
5. Oxygen has oxi number of -2 except as H2O2 when its -1
6. hydrogen has oxi number of +1

Question 8

reducing agent

Answer 8

readily donate electrons, and substance that is oxidised

Question 9

salt bridge

Answer 9

+ve cations move towards the cathode and -ve anions move towards the anode through the salt bridge to prevent build-up of ionic charge in half cell - completes the circuit

Question 10

oxidation always happens at the

Answer 10

anode