electrochemistry 🛁

Question 1

which electrode is the cathode and anode?

Answer 1

positive electrode: anode
negative electrode: cathode

Question 2

describe what happens at each anode

Answer 2

__ ions migrate towards the cathode. __ ions are discharged where they gain/lose electrons to form __

Question 3

what ions are present in aqueous solution?

Answer 3

H+, OH-, ions from compound

Question 4

what factors affect the ion preferentially discharged?

Answer 4

1) relative position of ions in the electrochemical series
2) concentration of electrolyte
3) nature of electrodes

Question 5

which ions will be preferentially discharged if present in a concentrated electrolyte?

Answer 5

lead, iron, zinc, iodide, bromide, chloride

Question 6

describe the process of preferential discharge (H+ and Na+)

Answer 6

sodium ions and hydrogen ions are attracted to the cathode. hydrogen ions are preferentially discharged because they gain electrons more easily to produce hydrogen gas

Question 7

describe what happens when copper electrodes are used

Answer 7

__ ions are attracted to the anode. however, both ions are not discharged, instead the copper anode, being a reactive anode, itself loses electrons. coper in the anode loses electrons to produce copper (II) ions which go into the electrolyte

Question 8

why does the copper(II) sulfate electrolyte not fade when using copper electrodes?

Answer 8

for each copper(II) ion discharged, another one is formed at the anode which goes into the solution, hence concentration of copper(II) ions stay the same

Question 9

applications of electrolysis

Answer 9

1) purification of copper
2) electroplating

Question 10

describe electron flow in a simple cell

Answer 10

electrons flow from the more reactive metal to the less reactive metal

Question 11

which electrodes are positive and negative and what ions do they attract?

Answer 11

more reactive metal: negative electrode
less reactive metal: positive electrode, attracts cations

Question 12

what reaction occurs at the zinc terminal? (zn and cu)

Answer 12

Zn -> Zn2+ + 2e-

Question 13

what reaction occurs at the copper terminal?

Answer 13

2H+ + 2e- -> H2

Question 14

briefly describe fuel cells

Answer 14

reactants are continuously supplied to produce electricity directly (2H2 + O2 -> H2O)

Question 15

advantages of fuel cellss

Answer 15

water is produced as the waste product, which can be drank by astronauts in space