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# Biology help? watch

1. Hello.

There's a question in my biology homework that I'm not entirely sure how to answer so I was wondering if someone could help me out a little? Here's the question;

Work out the concentration of the glucose solution if 4cm^3 of 20gdm^-3 of glucose was placed in a test tube with 1cm of water. Show your workings.

Thank you.
2. (Original post by a.mandie)
Hello.

There's a question in my biology homework that I'm not entirely sure how to answer so I was wondering if someone could help me out a little? Here's the question;

Work out the concentration of the glucose solution if 4cm^3 of 20gdm^-3 of glucose was placed in a test tube with 1cm of water. Show your workings.

Thank you.
15 what? What's your working? I did it quickly but got a different figure.
3. (Original post by a.mandie)
Hello.

There's a question in my biology homework that I'm not entirely sure how to answer so I was wondering if someone could help me out a little? Here's the question;

Work out the concentration of the glucose solution if 4cm^3 of 20gdm^-3 of glucose was placed in a test tube with 1cm of water. Show your workings.

Thank you.
You're in effect adding 1 cm3 of water so the original mass of glucose is now in 5 cm3 rather than 4 cm3 of solution. So the concentration will fall by a factor of 4/5
4. Thanks for the help guys but I figured out the answer and my friend confirmed it. You just divide 4 by 5 and then times by the 20. Final answer was 16gdm^-3.

I really appreciate everyone's help. Thanks x

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