J.R. S. answered • 10/04/21
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For this type of dilution problem, you can use the formula M1V1 = M2V1
M1 = initial molarity = 3.25 M
V1 = initial volume + ?
M2 = final molarity = 0.130 M
V2 = final volume = 0.5 L
(3.25)(x) = (0.130)(0.5)
x = 0.02 L = 20 mls.
You could also do it this way:
You want 0.5 L of 0.130 mol/L so you need 0.5 L x 0.130 mol/L = 0.065 mols of H2SO4
You have a solution that is 3.25 mol/L, so how many L do you need to get 0.065 mols?
0.065 mol x 1 L / 3.25 mol = 0.02 L = 20 mls
J.R. S.
tutor
Are you familiar with dimensional analysis? Get the units to cancel leaving you with what you want. mol x L/mol the mol cancel leaving you with L. If you did mol x mol/L you get mol squared / L. That's no good. Another way to look at is (x L)(3.25 mol/L) = 0.065 mol and solve for x which is 0.065/3.25. Hope this makes sense now. If not, please look up and read about dimensional analysis.
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10/04/21
Mallan S.
thank you so much.
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10/04/21
Mallan S.
I am so reatful i understand totally until we are 0.065 mol x 1 L / 3.25 mol = 0.02 L = 20 mls- why will we divide it and not 0,065mol x 3,25? sorry if I seem stupit but I really really need to understand it:) thank you10/04/21