A1.1 Water questions for IB Biology

39 questions on Water, written by Augment in the style of IB exam papers. Six of them are below in full, to answer on paper.

  • IB Biology
  • Part of A Unity and diversity
  • SL and HL

Questions by paper and level

SL and HL questions are for students at either level. HL only questions cover what only HL students study.

PaperSL and HLHL onlyAll
Paper 1A15520
Paper 1B415
Paper 211314
Every paper30939

Counted on

Questions to try

Written by Augment in the style of IB exams, not past papers. Answer them on paper, then check each one against its markscheme with a free account.

Question 1 · BIO-00001Paper 1A · 1 mark

Why is water described as the medium for life?

  1. A

    Water is the only molecule in cells that can form hydrogen bonds

  2. B

    The first cells originated in water and most processes of life still occur in water

  3. C

    Water provides the energy needed for most metabolic reactions

  4. D

    Water is the most abundant organic molecule in living cells

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Question 2 · BIO-00021Paper 1B · 10 marks

Students investigated capillary rise of water in soil. Glass tubes 50 cm long with an internal diameter of 2 cm were packed with dry, sieved sand of one of five particle sizes. The lower end of each tube was placed in 1 cm of water and the height of the wetting front (the top of the wet sand) was measured after 24 hours. Five tubes were set up for each particle size.

Mean particle diameter / mm

Mean height of wetting front after 24 h / cm

Standard deviation / cm

2.0

4.1

0.6

1.0

8.3

0.9

0.5

15.6

1.4

0.25

29.8

2.7

0.125

46.2

4.1

  1. (a)

    Identify the independent variable in this investigation.

    1 mark

  2. (b)

    State two variables that should have been kept constant.

    2 marks

  3. (c)

    Calculate the percentage increase in mean height of the wetting front when the mean particle diameter decreased from 0.5 mm to 0.25 mm.

    1 mark

  4. (d)

    Describe the relationship between particle diameter and the height of the wetting front.

    2 marks

  5. (e)

    Explain the results in terms of the properties of water.

    3 marks

  6. (f)

    Suggest one limitation of using sieved sand in tubes as a model of capillary rise in natural soil.

    1 mark

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Question 3 · BIO-00026Paper 2 · 7 marks

The black-throated loon (Gavia arctica) flies between lakes and dives under water to catch fish. The ringed seal (Pusa hispida) swims in Arctic seawater and rests on the ice in air. The table compares some physical properties of air and water at 20 °C.

Property

Air

Water

Density / kg m-3

1.2

998

Viscosity / mPa s

0.018

1.00

Thermal conductivity / W m-1 K-1

0.025

0.60

Specific heat capacity / J g-1 K-1

1.0

4.2

  1. (a)

    Calculate how many times greater the thermal conductivity of water is than that of air.

    1 mark

  2. (b)

    Using the data, outline why a streamlined body shape is more important for a loon swimming under water than for a loon flying.

    2 marks

  3. (c)

    Explain how the difference in density between air and water affects the loon when it dives and when it flies.

    2 marks

  4. (d)

    Using the data, explain why a ringed seal loses heat faster when swimming than when resting on the ice in air at the same temperature.

    2 marks

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Question 4 · BIO-00002Paper 1A · 1 mark

What makes a water molecule polar?

  1. A

    The oxygen and hydrogen atoms are held together by ionic bonds

  2. B

    Hydrogen bonds link the oxygen atom to the hydrogen atoms within the molecule

  3. C

    The hydrogen atoms carry a full positive charge and the oxygen atom a full negative charge

  4. D

    The oxygen atom attracts the shared electrons more strongly than the hydrogen atoms do

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Question 5 · BIO-00022Paper 1B · 9 marks

Students investigated the effect of detergent on the surface tension of water. A clean coin was placed flat on a bench and drops of a detergent solution were added one at a time from the same plastic dropper until the liquid overflowed the edge of the coin. The number of drops held was recorded. This was repeated ten times for each of five concentrations of detergent. The graph shows the mean number of drops held; error bars show ±1 standard deviation.

Line graph with error bars: mean drops held on a coin fall from 38.4 at 0 % detergent to 31.2 at 0.05 %, 24.6 at 0.10 %, 19.8 at 0.20 % and 18.9 at 0.50 %. Error bars about ±2 to ±2.6 drops.
  1. (a)

    State the dependent variable.

    1 mark

  2. (b)

    Suggest why the same dropper was used for every trial.

    1 mark

  3. (c)

    Calculate the percentage decrease in the mean number of drops held between 0 % and 0.20 % detergent.

    1 mark

  4. (d)

    Evaluate the claim that 0.50 % detergent reduces surface tension more than 0.20 % detergent.

    2 marks

  5. (e)

    Explain why pure water can form a dome above the rim of the coin.

    2 marks

  6. (f)

    Pond skaters (Gerris lacustris) live on the surface of ponds. Suggest the consequences for pond skaters of detergent entering a pond.

    2 marks

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Question 6 · BIO-00027Paper 2 · 8 marks

Water molecules are polar and form hydrogen bonds with each other.

  1. (a)

    Draw a labelled diagram showing three water molecules and the hydrogen bonds between them.

    3 marks

  2. (b)

    State the type of bond between the oxygen atom and a hydrogen atom within a water molecule.

    1 mark

  3. (c)

    Explain why a water molecule is polar.

    2 marks

  4. (d)

    Outline why water is described as the medium for life.

    2 marks

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The notes on A1.1 Water

More questions in Unity and diversity

  1. A1.1WaterThis page
  2. A1.2Nucleic acids
  3. A2.1Origins of cellsHL only
  4. A2.2Cell structure
  5. A2.3VirusesHL only
  6. A3.1Diversity of organisms
  7. A3.2Classification and cladisticsHL only
  8. A4.1Evolution and speciation
  9. A4.2Conservation of biodiversity

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