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    The table below shows some features of gas exchange of a fish at rest.

    Volume of oxygen absorbed by the gills from each dm3 of water /cm3 = 7
    Mass of fish / kg = 0.4
    Oxygen required by fish / cm3 kg–1 hour–1 = 90

    (i) Calculate the volume of water that would have to pass over the gills each hour
    to supply the oxygen required by the fish. Show your working.

    Can anyone tell me how to work out this question.
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    Correct answer of 5.1 or 5.14 (dm3) = 2 marks;
    One mark for incorrect answers that show 36 or 0.4 x 90 or 90 ÷ 7;
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    (Original post by 11wiltshirel)
    Mark Scheme:

    Correct answer of 5.1 or 5.14 (dm3) = 2 marks;
    One mark for incorrect answers that show 36 or 0.4 x 90 or 90 ÷ 7;
    Thanks, I'm still unsure how to get to the answer of 5.1
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    Fish need 90cm3 O2 per kg per hour

    Fish weighs 0.4kg, so 0.4 x 90 = 36cm3 O2 needed per hour

    7cm3 of O2 per dm3 water,
    so 36cm3 / 7cm3 = 5.14... dm3 water
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    (Original post by westcw13)
    Fish need 90cm3 O2 per kg per hour

    Fish weighs 0.4kg, so 0.4 x 90 = 36cm3 O2 needed per hour

    7cm3 of O2 per dm3 water,
    so 36cm3 / 7cm3 = 5.14... dm3 water
    Thanks!
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    IS this an A Level Question ?
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    (Original post by sabrine12)
    IS this an A Level Question ?
    yeah
 
 
 
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