Grade 12 · Practice problems
Water & carbohydrates & lipids
50 written problems across two levels — 33 foundational · 17 advanced. Work through them on paper, then reveal every answer to check. These are not graded and are counted separately from adaptive practice.
1. FoundationalWhat makes water a polar molecule?
2. FoundationalWhat weak bond forms between neighbouring water molecules?
3. FoundationalName the attraction of water molecules to one another.
4. FoundationalName the attraction of water to other surfaces.
5. FoundationalWhat property lets small insects walk on water?
6. FoundationalDoes ice float or sink in water?
7. FoundationalWhy is ice less dense than liquid water?
8. FoundationalWhat is often called the 'universal solvent'?
9. FoundationalWhat does water's high specific heat allow it to do?
10. FoundationalHow many covalent bonds does carbon form?
11. FoundationalCarbon-based molecules are called ___ molecules.
12. FoundationalWhat is a monomer?
13. FoundationalWhat is a polymer?
14. FoundationalName the reaction that joins monomers and removes water.
15. FoundationalName the reaction that splits polymers by adding water.
16. FoundationalWhich three elements make up carbohydrates?
17. FoundationalGive the chemical formula of glucose.
18. FoundationalWhat is a single sugar unit called?
19. FoundationalWhich sugar does the blood carry as fuel?
20. FoundationalTwo monosaccharides joined form a ___.
21. FoundationalName the disaccharide known as table sugar.
22. FoundationalName the storage polysaccharide in plants.
23. FoundationalName the storage polysaccharide in animals.
24. FoundationalName the structural polysaccharide in plant cell walls.
25. FoundationalWhy is cellulose called dietary fibre for humans?
26. FoundationalDo lipids mix with water?
27. FoundationalA triglyceride is made of glycerol and three ___.
28. FoundationalWhat is a fat with only single bonds in its tails called?
29. FoundationalWhat is a fat with double-bond kinks, liquid at room temperature, called?
30. FoundationalWhich lipid forms cell membranes?
31. FoundationalWhat arrangement do phospholipids form in water?
32. FoundationalName a steroid found in animal cell membranes.
33. FoundationalWhich stores more energy per gram, fat or carbohydrate?
34. AdvancedExplain why water can dissolve salt but oil cannot.
35. AdvancedExplain why sweating cools the body.
36. AdvancedExplain why lakes freezing from the top down protects fish.
37. AdvancedPredict the products when two glucose molecules undergo dehydration synthesis.
38. AdvancedWhen a polymer is digested in your gut, which reaction occurs and what is added?
39. AdvancedExplain why saturated fats tend to be solid while unsaturated fats are liquid.
40. AdvancedExplain how a phospholipid's structure leads it to form a bilayer in water.
41. AdvancedFructose and glucose share the formula C6H12O6; what is such a pair called and why do they behave differently?
42. AdvancedExplain how carbon's bonding gives rise to such molecular variety.
43. AdvancedExplain why water is described as taking part directly in building and breaking polymers.
44. AdvancedExplain why fat is a better long-term energy store than glycogen.
45. AdvancedA cell membrane is placed in a nonpolar solvent; predict what happens to the bilayer.
46. AdvancedExplain how water's high specific heat helps a large organism on a hot afternoon.
47. AdvancedExplain why fat-soluble vitamins need dietary fat to be absorbed.
48. AdvancedConstruct an argument that without water's polarity, cellular life as we know it could not exist.
49. AdvancedExplain why blood must package lipids with proteins for transport but not glucose.
50. AdvancedExplain how the same glucose monomer can build both an energy store and a rigid structure.