Jan 7--Diluting Solutions

Key Idea: The moles of solute before and after diluting is constant.

Moles solute before = Moles solute after

M1 L1 = M2 L2

For example:

A concentrated HCl is 24.5 mole/L. How would you make up 125 mL of 2.53 mole/L of HCl?

 1. Solve for how much volume first.(L1)

 2. From the fomula : M1L1 = M2L2

 3. 24.5 mole/L x L1 = 125 mL x 2.53 mole/L
             L1= (125 mL x 2.53 mole/L) / 24.5 mole/L
             L1= 12.9 L