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Method For Solution Calculations

I need to know the method in which you can work out questions such as these:

25.0cm3 of 0.020mol/dm3 sulphuric acid neutralises 18.6cm3 of barium hydroxide solution

H2SO4 + Ba(OH)2 -> BaSO4 + 2 H2O (Ratio is 1:1)

a)Work out the concentration of barium hydroxide solution in mol/dm3

b)Work out the concentration of barium hydroxide solution in g/dm3

ASAP with working out pleeease!

Thanks

Reply 1

nylia97

First you would need to find the number of moles of Ba(OH)2.
In order to do this, you will calculate the number of moles of sulfuric acid. (make sure you convert the volume into dm3) Since they have a 1:1 ratio, the number of moles would be equal.

For the concentration in g/dm3, use the Mr and number of moles to find the mass.

:smile:

hope it helps

Reply 2

xCowBoyx

Original post by nylia97

hope it helps

Would you please just do the working out so i can visualize it and understand a lot better! (And how to convert volume into dm3?)
Thanks

Reply 3

nylia97

Original post by xCowBoyx

Would you please just do the working out so i can visualize it and understand a lot better! (And how to convert volume into dm3?)
Thanks

Yea, sure. I do by simply eliminating the units.

(cm3/1000 to convert it to dm3.)

a) to find the number of moles sulfuric acid:
volume x concentration
= (25/1000)dm3 x 0.020mol/dm3
=0.0005moles

concentration of Ba(OH)2 = moles/volume

b) I don't have a periodic table with me but mass=moles x Mr
and then you can just divide the mass by the volume

:biggrin: