electrolysis - Chemistry Flashcards
(23 cards)
what is the definition of electrolysis?
using electricity to break down ionic compounds
what is an electrolyte?
a liquid or solution that contains an ionic compound
give the different electrodes and state which one is negative and which one is positive?
anode - positive
cathode - negative
why does electrolysis have to be carried out on a molten or aqueous solution?
because there are freely moving ions
label the equipment needed for electrolysis
- beaker
- electrodes
- wire
- power supply
define ‘discharged’
when an ion becomes an atom through gaining or losing electron(s)
what is the negatively charged ion called in electrolysis?
anion
what is the positively charged ion called in electrolysis?
cation
from which electrode do electrons flow from?
the anode
what does it mean when an ion becomes oxidised?
the ion loses electrons
Oxidation
Is
Loss of electrons
what does it mean when an ion becomes reduced?
the ion gains electrons
Reduction
Is
Gain of electrons
finish the half equation:
2H⁺ + 2e⁻ → ___
H₂
finish the half equation:
Al³⁺ + ___ → Al
3e⁻
finish the half equation:
2Cl⁻ → ___ + 2e⁻
Cl₂
finish the half equation:
4OH⁻ → ___ + ___ + 4e⁻
2H₂O + O₂
if a metal is less reactive than carbon, then we can form what type of reaction to form it’s pure metal?
displacement reaction
label the reactivity series
Please - Potassium
Stop - Sodium
Calling - Calcium
Me - Magnesium
A - Aluminium
Cute - Carbon
Zebra - Zinc
Instead - Iron
Try - Tin
Learn - Lead
How - Hydrogen
Copper - Copper
Saves - Silver
Gold - Gold
state the 2 different ways to extract pure metal from it’s oxide
- reduction with carbon
- electrolysis
state how bauxite is converted into molten aluminium oxide
- bauxite is purified into aluminium oxide
- aluminium oxide is mixed with cryolite to lower melting point
- aluminium oxide is melted into molten aluminium oxide
what does it mean when a substance is aqueous?
a solution dissolved in water
what is the rule for determining which ion is discharged at the cathode in aqueous solutions?
the ion of the least reactive element is discharged
what is the rule for determining which ion is discharged at the anode for an aqueous solution?
if a halide is present, it will be discharged, otherwise hydroxide will be discharged
what is a halide?
any element from group 7
