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Simple dilutions q. watch

1. If the concentration of a reagent is 0.0400 mol dm-3 and 1cm3 of water is being added to it... Does it mean that the new concentration of the reagent is 0.039 mol dm-3? By 0.400 mol dm-3 - 0.001dm3
2. (Original post by MacOne)
If the concentration of a reagent is 0.0400 mol dm-3 and 1cm3 of water is being added to it... Does it mean that the new concentration of the reagent is 0.039 mol dm-3? By 0.400 mol dm-3 - 0.001dm3
It all depends on the volume of your reagent used ...

Calculate the moles of reagent by concentration x volume in litres.

Divide the moles of reagent by the new volume in litres ...
3. (Original post by charco)
It all depends on the volume of your reagent used ...

Calculate the moles of reagent by concentration x volume in litres.

Divide the moles of reagent by the new volume in litres ...

Conc of reagent - 0.0400 mol dm-3
Vol reagent - 5cm3 (0.005L)

0.0400 x 0.005L = 0.0002M

0.0002M/ 0.004L (addition of 1cm3 of water) = 0.05 mol dm-3 (new conc)

This is what I don't understand... Wouldn't I expect to see a decrease in its concentration?

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Updated: March 9, 2013
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