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Dilution calculations are common in both chemistry courses and in lab.  The calculations are actually quite simple to perform as they only use one equation M1V1 = M2V2   where

M1 = the initial concentration
V1 = the initial volume
M2 = the final concentration
V2 = the final volume

The concentration is usually given in M (mol/L) and the volume can be in any unit you want, as long as you use the same units for V1 and V2

Example Question:

Mixing H2SO4?

"What volume, in mL, of concentrated sulfuric acid
(18.0 M H2SO4) is needed to prepare 2.50 L of a 1.00 M
solution? How would I do this problem?"


We'll start with our equation

M1V1 = M2V2

where M1 = the initial concentration (18.0M)
V1 = the volume of that solution you will need
M2 = the final concentration you want (1.00M)
V2 = the final volume of solution you want (2500mL, or 2.5L)

so you plug the numbers in, we're going to use 2500mL so it gives us our answer in mL.

18.0 (V1) = 1.00 (2500mL)
V1 = 2500 / 18
V1 = 138.89 mL

So you would measure out 138.89 mL of sulfuric acid and dilute to 2500mL (Add 2361.11 mL of water)

*** VERY IMPORTANT - do not pour water into a concentrated acid solution.  The mixing of water and a concentrated acid is an exothermic process (creates heat).  Instead, get about 1/2 to 3/4 of the water you need, add the concentrated acid to that, then finish diluting with the rest of your water.

Did I miss something?  Let me know


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