Measuring Concentration

Strength of a Solution

Dilute – low amount of solute dissolved in solvent

Concentrated – high amount of solute dissolved

Dilute vs. Concentrated

One way to measure concentration Grams of solute per Liter of solution

g/L

Example What is the concentration (in g/L) of a

solution composed of 45g of KCl dissolved to form 1.5L of solution?

Example How many grams of NaOH are dissolved in

500ml of solution with a concentration of 0.75 g/L?

Example What volume of water is needed to form a

0.25 g/L solution if you start with 15g of CuS?

Milligrams of solute per liter of solution

Parts per Million (ppm)

Example What is the concentration (in ppm) of a

solution made by dissolving 15g of MgO in 250ml of water?

Example

How many grams of CaCl2 are needed to form 200ml of a 25ppm solution?

Mass of solute/ mass of solution x 100

% by Mass

Find the % by mass is 25g of NaCl is dissolved in 150g of water.

Example

Example What mass of water is needed to form a

15% solution starting with 20g KCl?

Example What mass of SrO must be dissolved in

500g of water to form a 11% solution?