Molar Concentration

Welcome back from winter break and guess what? It hasn't been easy and work has been piling up... but that's okay because nothing says a little knowledge of Molar Concentration will cheer you up!

Molar Concentration is able to compare the amount of solute dissolved in a certain volume of solution.
Or in other words Molar Concentration is represented by M and it has the units of "mols/L."
The formula is Molarity = moles of solute (mol)/volume of solution (L)
In other words it's M = mol/L.
You can always rearrange them like... mol = M x L and L = mol/M.

Let's do some exercises, shall we?
Okay..
1) Calculate molar concentration that has a solution of 0.505 moles of CaCl2 in 1.600 L of solution.
2)Calculate the number of grams of sodium hydroxide in 2.30 L of a 0.7 M NaOH solution.
3) How many grams of AlCl3 are contained in 80.0 mL of 1.5 mol/L of AlCl3.
4) Calculate the volume of L of 0.780 M NaCl solution that contains 55.21 g NaCl.

* Remember to convert your mL to L!*

Answers:
1) M = 0.505 moles of CaCl2 / 1.600L
         =  0.316 mol/L
2) 2.30 L 0.7 M = 1.61
    MM of NaOH = 40 g/mol
    0.316 mols of NaOH x 40 g NaOh / 1 mol of NaOH
    = 12.64g of NaOH
3)
4) MM of NaCl = 58.5 g/mol
    55.21 g x 1 mol / 58.5 g
    = 0.944
L solution = 9.44444 moles of NaCl / 0.780
                = 12.108L