Molarity & Dilution By: Wes Corkum

Molarity concentration is the measure of how much solute is dissolved in a given amount of solution. The main measure of concentration in chemistry is molarity, written as M. Molarity is given by the number of moles of solute per 1 litre of solution. The units are always Moles/Litres

Ionization When a molecule dissociates into its atoms, we can find the molarity of the atoms. This is done by using the mole ratios. For example, if we had BaCl 2 with a molarity of 1, when it ionized we would have 1 mol/L of Ba and 2 mol/L of Cl

Example BaCl 2 -> Ba+ + 2Cl - for every 1 mol of BaCl 2 there is 1 mol of Ba and 2 mol of Cl.

Dilution Diluting a solution means adding volume without adding solute most chemicals used in labs have been diluted from their original molarity. After a substance has been diluted, we have a formula to find its new molarity.

M 1 V 1 =M 2 V 2 This equation can be used to find molarity or volume, before or after a dilution has occurred. It says that the molarity multiplied by the volume before the dilution is equal to the molarity multiplied by the volume after the dilution.

Example 10ml of 12 molar hydrochloric acid is added to 200ml of water. Find the molarity of the new solution.

First you should realise that you have been given the molarity and volume before, and can find the volume afterward by adding the volume of the water and the acid. Next, convert your volume into litres. Your equation should look like this. (12)(0.01) = (M)(0.21) now all you need to do to find your molarity is divide by 0.21, and you get an answer of 0.57 mol/L

Bibliography Chem 12 blue booklet