electrolysis + reactivity

Question 1

what is electrolysis

Answer 1

splitting of ionic substances using electricity

Question 2

what are electrolytes

Answer 2

ionic compounds either in molten state or dissolved in water

Question 3

what are electrodes made of and why

Answer 3

-usually graphite
-conductive and inert

Question 4

positive electrode

Answer 4

anode

Question 5

negative electrode

Answer 5

cathode

Question 6

postive ions

Answer 6

cations

Question 7

negative ions

Answer 7

anions

Question 8

what happens when ions reach an electrode

Answer 8

gain or lose electrons so form atoms/molecules of an element

Question 9

why do electrolytes have to be in molten state/dissolved

Answer 9

ions are free to move therefore can carry charge

Question 10

why are the electrodes inert

Answer 10

so electrolyte doesn’t form a new substance by reacting with electrodes

Question 11

reactivity series

Answer 11

potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
hydrogen
copper
silver
gold

Question 12

what does electrolysing water do

Answer 12

splites water molecules into hydrogen and oxygen

Question 13

equation for electrolysis of water

Answer 13

2H2O (l) -> 2H2 (g) + O2 (g)

Question 14

what ions could be produced in electrolysis of water

Answer 14

OH- and H+

Question 15

how do you know what positive ion is discharged

Answer 15

element lower in reactivity series

Question 16

how do you know what negative ion is discharged

Answer 16

a halide ion before OH-

Question 17

halide ions

Answer 17

group 7: F-, Cl-, Br-, I-

Question 18

what does OH- produce when discharged

Answer 18

O2

Question 19

what is oxidation

Answer 19

-loss of elctrons
-gain of oxygen

Question 20

what is reduction

Answer 20

-gain of electrons

Question 21

where does reduction happen

Answer 21

cathode

Question 22

where does oxidation happen

Answer 22

anode

Question 23

reduction half equation example

Answer 23

Na+ + e- -> Na

Question 24

oxidation half equation example

Answer 24

2Cl- -> Cl2 + e-

Question 25

what side is the electron on of a reduction half equation

Answer 25

left

Question 26

what side is the electron on of a oxidation half equation

Answer 26

right

Question 27

metal + water -> ?

Answer 27

metal hydroxide + hydrogen

Question 28

metal + acid -> ?

Answer 28

salt + hydrogen

Question 29

what determines reactivity

Answer 29

its ability to lose electrons

Question 30

why does reactivity increase as you go down group 1

Answer 30

-number of electron shells increases -outermost electron is further from positive nucleus -weaker forces of attraction so less energy is required to overcome

Question 31

describe a displacement reaction as redox reaction

Answer 31

during displacement, the more reactive metal loses electrons (is oxidised) + less reactive metal gains those electrons (is reduced).

Question 32

how are metals less reactive than carbon extracted

Answer 32

reduction with carbon

Question 33

acid + metal oxide -> ?

Answer 33

salt + water

Question 34

acid + metal hydroxide -> ?

Answer 34

salt + water

Question 35

acid + metal carbonate -> ?

Answer 35

salt + water + carbon dioxide