Hydrogen peroxide vol

Just wondered how anyone would dilute 100 vol of hydrogen peroxide, this is equivalent to 8.8 mol. But how do i dilute this to reach 1 mol, 0.8 mol, 0.6 mol etc. Whatever i seem to do it doesn't dilute to these exact mols, (and an explanation of the calculation would be great, it just isn't happening in my head!)

Thanks

Reply 1

lei_armstrong

Swinely

Sorry to say but you won't get nice ratios! Why not use 20 vol instead? Or dilute it by vols i.e use 100 vol, 80 vol, 60 vol, 40 vol and 20 vol for your experiment?

Anyway you would divide 100 by 8.8 to get 1 moldm-3 then just multiply that by whatever concentration you are after. The ratio will be value : (100-value)

e.g. for 0.8 mol solution

100/8.8 = 11.3636

11.3636 x 0.8 = 9.0909

so your ratio of 100 vol hydrogen peroxide to distilled water for 0.8 mol will be
9:91 (rounded to the nearest whole number)

i.e. if you wanted to make 500cm3 of the 0.8mol solution then you would mix together 45cm3 of 100vol hydrogen peroxide with 455cm3 of distilled water
(500/100 = 5, 5 x 9 = 45, 5 x 91 =455)

also:

1.0 mol ratio will be 11:89

0.6 mol ratio will be 7:93

hope this helps!

Reply 2

Swinely

The only problem is then that the equations would be harder to work out as they would not have whole numbers of moles used? Luckily its a simple equation anyway though :p:

.

Thanks for the help though,I might have to use the vols method, rep on the way.

Looks like i'll be seeing you at warwick btw!
edit: If i get the grades too!

Reply 3

lei_armstrong

Swinely

The only problem is then that the equations would be harder to work out as they would not have whole numbers of moles used? Luckily its a simple equation anyway though :p:

.

Thanks for the help though,I might have to use the vols method, rep on the way.Looks like i'll be seeing you at warwick btw!

yeah, using the equations above would give you quite inaccurate number of moles as you have to round them! it's alot easier if you use vols as you get the following:

100 vol = 8.80 mol
80 vol = 7.04 mol = 4:1 ratio
60 vol = 5.28 mol = 3:2 ratio
40 vol = 3.52 mol = 2:3 ratio
20 vol = 1.76 mol = 1:4 ratio

also ~ yay, warwick! lol yup will be seeing you there (hopefully if i get the grades)