Why water behaves so differently from similar molecules, how its solvent properties cause hardness and leaching, and how water is treated for domestic use.
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.
Every Caribbean household depends on it, and yet water is one of the strangest substances known: ice floats, and it dissolves almost everything.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
See how hydrogen bonds link water molecules.
Copy these into your notebook in your own words — that is how they stick.
Gives water high m.p./b.p.; ice less dense than water.
High: stable temperatures.
Dissolves ionic and polar substances.
Hydrogencarbonates; removed by boiling.
Sulfates/chlorides; not removed by boiling.
Boiling, washing soda, ion exchange.
Water dissolves minerals/nutrients from soil.
Screening, coagulation, sedimentation, filtration, chlorination.
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 (18 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [18 marks]
Hard water causes problems in homes and industry, and water must be treated before it can be used for drinking.
(a) (a) State two unique properties of water and one way each is important to living organisms. [4]
(b) (b) Distinguish between temporary and permanent hardness. [3]
(c) (c) Write an equation for the removal of temporary hardness by boiling. [2]
(d) (d) Describe how washing soda softens hard water and write an ionic equation. [3]
(e) (e) Name two stages in the treatment of water and give the purpose of each. [4]
(f) (f) State one advantage and one disadvantage of hard water. [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.