Factors that affect the products of electrolysis, the Faraday constant, calculating the mass or volume of a product from current and time, and industrial electrolysis: electroplating, purification, aluminium and chlorine.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
A gold-plated watch has only a thin layer of gold. Faraday’s constant lets us calculate exactly how much metal a current deposits in a given time.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
96 500 C/mol: charge on 1 mole of electrons.
Q = I × t (C = A × s).
Q ÷ 96 500.
Moles of electrons ÷ charge on the ion.
2 e⁻ per H₂; V = n × 24 dm³.
4 e⁻ per O₂.
Al₂O₃ in molten cryolite; graphite anodes are replaced.
Object = cathode; plating metal = anode.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Chemistry Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (16 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [16 marks]
A current of 0.50 A is passed through copper(II) sulfate solution for 32 minutes 10 seconds (1 930 s) using copper electrodes. Cu = 63.5; F = 96 500 C/mol.
(a) (a) Calculate the quantity of electricity passed. [2]
(b) (b) Calculate the number of moles of electrons. [2]
(c) (c) Write the half-equation at the cathode and calculate the mass of copper deposited. [4]
(d) (d) State what happens to the anode and why the colour of the solution does not change. [3]
(e) (e) Explain why cryolite is used in the extraction of aluminium. [2]
(f) (f) Describe how an iron key could be plated with silver. [3]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.