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Biology conc. question

Hi everyone,

I'm stuck on this question and would really appreciate if someone can explain how to work this out!

'Describe how you would use a 1.0 mol dm–3 solution of sucrose to produce 30 cm3 of a 0.15 mol dm–3 solution of sucrose.'

Reply 1

macpatgh-Sheldon

SIMPLE MATHS, yeah?

You have 0.15 moles sucrose in 1 dm^3 yes? = same as 0.15 moles in 1L [cos dm^3 is 100 mm X 100 mm X 100 mm [deci means 1/10th so 1/10th of a litre, yes?] = 10 cm X 10 cm X 10 cm = 1000 cm^3 which is one litre.

You need a total of 30/1000 [there are 1000 cm^3 in 1 L, yeah?] X 0.15 moles, still with me?

So you need 0.45/100 = 4.5 X 10^-3 moles total

This needs to be made from a 1M solution given to you, yeah? = it has 1 mole in a litre.

I have given you enough clues - now work it out [I'll be generous - one more clue - from the above you just need to work out how many times you need to dilute your stock solution]

Be safe!
M

Reply 2

MV123456

Thank you!