Solution Preparation

Solutions are shipped in concentrated form to minimize shipping costs. Therefore, they must be prepared before they can be used.

The formula M1L1 = M2L2 is used to prepare solutions.
The most important thing to remember is that the MOLES on one side MUST EQUAL the MOLES on the other side!


Example:
I have 2.00 L of 16.0 M of HCl. I need 0.800 L of 2.00 M HCl.
Solve for L1.
(16.0M1)(L1) = (0.800L2)(2.00M2)
L1 = 0.100 L

Let's do one more example:
You have 11.6 mol/L of HCl. How would you make up 250 mL of 0.500 mol/L?
Solve for L1.
(11.6M1)(L1) = (0.25L2)(0.500M2)
L1 = 0.011 L acid
Then, you subtract the original volume by the amount of acid required.
0.25 - 0.011 = 0.239 L
Therefore, you would need 0.011 L of acid and 0.239 L of water.

Here's a video that explains it all step by step...