|Themes > Science > Chemistry > General Chemistry > Solution and Solubility > Solubility of Solutes and Aqueous Solutions > Solution Index > Molarity|
The molarity of a solute is the number of moles of that solute divided by the volume of the solvent in liters. It's the handiest measure for most aqueous solutions, since we are usually interested in the number of moles of the solute, but we work with volumes.
To figure out the molarity of a solution, simply work out the number of moles of the solute (Probably from the molecular weight) and divide by the volume of the solvent
Example 1: If you have 10.0 grams of NaCl, table salt, and dissolve it in 500 ml of water, what is the molarity of the solution?
Solution 1: First, work out the number of moles of salt. NaCl has a molecular weight of 58.43 g/mole, so we have
Example 2: How many moles of Ba(NO3)2 are there in 250 ml of a 0.450 M solution?
Solution 2: Again, we need to convert milliliters to liters, so