# Biology ratios

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AQA Jan 10 paper qs 5

any ideas anyone, can do ratio but can't head round this one, answer is 1.08 !!

how do you work it out ahhhhhhh

Posted: 14-05-11 11:14 by KB

Students investigated the effect of different concentrations of sodium chloride solution on
discs cut from an apple. They weighed each disc and then put one disc into each of a range
of sodium chloride solutions of different concentrations. They left the discs in the solutions
for 24 hours and then weighed them again. Their results are shown in the table.

Concentration of sodium chloride solution  /moldm–3

Mass of disc at start g

Mass of disc at the end g

Ratio of mass at start to mass at end

0.00 16.1 17.2 0.94

0.15 19.1 20.2 0.95

0.30 24.3 23.2 1.05

0.45 20.2 18.7 1.08

0.60 23.7 21.9

0.75 14.9 13.7 1.09

5 (a) (i) Calculate the ratio of the mass at the start to the mass at the end for the disc
placed in the 0.60 moldm–3 sodium chloride solution.

hopefully this will help, hasnt copied too good

Posted: 14-05-11 11:26 by KB

I was wondering the same thing! You divide the start mass by the end mass and round it to 3 decimal places.

23.7 - 21.9 = 1.08219178 = 1.08

Posted: 20-05-15 17:50 by Sonia H