CAIE A-Level Biology AS 2.4 Water Questions
Practise CAIE AS Biology 2.4 by linking water's hydrogen bonds to solvent action, temperature stability and evaporative cooling.
- Syllabus
- 2028–2030
- Course
- Biology 9700
- Level
- AS
Exam points
- Explain water's polarity and hydrogen bonding: δ+ hydrogen is attracted to δ− oxygen on a neighbouring molecule.
- Relate hydrogen bonding to water's high specific heat capacity and the stable temperatures it helps maintain.
- Relate hydrogen bonding to water's high latent heat of vaporisation and evaporative cooling in organisms.
- Explain how water's polarity lets it dissolve ions and polar molecules for reactions and transport.
Covered syllabus points
Question 1
[Maximum number: 1]
Which properties of water are dependent on hydrogen bonding between water molecules?
cohesion
high latent heat of vaporisation
solvent action
high specific heat capacity
key
✓ = dependent
χ= not dependent
✓
✓
✓
χ
✓
✓
χ
✓
✓
×
✓
✓
x
✓
✓
✓
B
Question 2
[Maximum number: 1]
Hydrogen bonding explains many of the properties of water, including the high latent heat of vaporisation and high specific heat capacity.
For which processes in plants is hydrogen bonding in water important on hot sunny days?
1 preventing denaturation of enzymes in leaves
2 reducing water loss by evaporation
3 allowing leaves to cool down quickly at night
4 holding the column of water in xylem vessels together
A
1, 2, 3 and 4
B
1, 2 and 4 only
C
1, 3 and 4 only
D
2 and 3 only
B
Question 3
[Maximum number: 1]
What is the maximum number of hydrogen bonds that can form between a single water molecule and other water molecules?
A
1
B
2
C
3
D
4
D
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