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Practical skills assessed in a written examination

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Question 3

Dissolved oxygen saturation concentration is a measure of the maximum amount of oxygen that can be dissolved in water under given conditions of temperature and salinity.

The graph below shows the typical dissolved oxygen concentration at saturation for water of different temperatures and salinity levels.

Graph showing the dissolved oxygen concentration on the y-axis ranging from 4.0 to 14.0 mg dm^-3, plotted against water temperature in degrees Celsius on the x-axis ranging from 0 to 40. Five curves are shown corresponding to salinity levels: 0, 10, 20, 30, and 40 g kg^-1.

Determine the percentage decrease in the dissolved oxygen saturation concentration when freshwater (salinity of 0 g kg−10\text{ g kg}^{-1}0 g kg−1) at 5 ∘C5\,^{\circ}\text{C}5∘C is replaced with saline water of salinity 30 g kg−130\text{ g kg}^{-1}30 g kg−1 at 30 ∘C30\,^{\circ}\text{C}30∘C. Give your answer to one decimal place.

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Practical skills assessed in a written examination Questions

  1. A Level
  2. /Biology
  3. /Practical skills assessed in a written examination