Molarity

The concentration of a solution is a measure of the amount of solute in a specific quantity of solvent. Chemists express solution concentrations as molarity (abbreviation M). Molarity is defined as

Example of solution preparation

We want to prepare a 500.0 mL of a 0.0540 M of NaOH.

Here are the steps:

Step 1: Convert 500.0 mL to liter.

Step 2: Convert liters to moles using molarity as the conversion factor.

Step 3: Convert moles of NaOH to mass of NaOH (in grams) using molar mass as the conversion factor.

From the above three steps, we need to weigh out 1.08 grams of NaOH.

Directions to prepare the solution

Step 1: Weigh out 1.08 grams of NaOH.

(Note: This is not the colour of NaOH.)

Step 2: Transfer the solid to a 250 mL beaker that is partly filled with distilled water. Dissolve the solid in the beaker.

Step 3: Quantitatively transfer the solution in the beaker to the volumetric flask. Fill the flask with distilled water up to the mark. Stopper the volumetric flask and shake vigorously to ensure the solution is well mixed.

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Making a solution

Content suitability

BCIT courses: CHEM 0011