chemical changes Flashcards
(4 cards)
1
Q
explain why aluminium is extracted by electrolysis and not carbon reduction
A
- aluminium is more reactive than carbon
- so carbon cannot displace it
2
Q
give an observation of a reaction between zinc and copper sulfate, why
A
- blue solution turns colourless
- zinc has displaced copper
3
Q
identify product at cathode and why for copper sulfate solution
A
- oxygen gas formed
- OH- ions preferentially discharged over sulfate ions
- sulfate ions remain in solution
4
Q
which acid is more dilute and why? 0.1 mol/dm3 or 1 mol/dm3
A
0.1 - fewer moles of acid per unit volume compared to other
