Definitions of acid, base, alkali, salt, anhydride and the types of oxide, the pH scale, strong and weak acids and alkalis, and acids in living systems.
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.
Lime juice removes rust stains, vinegar preserves food and antacids soothe a stomach. They all depend on acids and bases.
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.
H⁺ (proton) donor; replaceable hydrogen.
Base accepts protons; alkali is a soluble base giving OH⁻.
Hydrogen of an acid replaced by a metal or NH₄⁺.
Non-metal oxides; acid anhydrides.
Metal oxides / Al₂O₃, ZnO, PbO / CO, H₂O, NO.
0–14: below 7 acid, 7 neutral, above 7 alkaline.
Completely ionised (high [H⁺] or [OH⁻]).
Partially ionised; reversible.
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 (17 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [17 marks]
A student tests solutions of hydrochloric acid, ethanoic acid, sodium hydroxide and ammonia solution, each of concentration 0.1 mol/dm³.
(a) (a) Define acid and alkali. [3]
(b) (b) State the approximate pH of each solution. [4]
(c) (c) Explain why the pH of ethanoic acid is higher than that of hydrochloric acid at the same concentration. [3]
(d) (d) Name an instrument that measures pH more accurately than universal indicator. [1]
(e) (e) Classify the oxides CO₂, MgO, ZnO and CO as acidic, basic, amphoteric or neutral. [4]
(f) (f) Name an acid in living systems and give a use or effect. [2]
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.