1. Molar Concentration

2. Molarity is the number of moles of solute that can dissolve in 1 L of solution. Molar concentration (mol/L) = Amount of solute (mol) Volume of solution (L) C n V

3. What is the concentration, in mol/L, of a solution formed by dissolving 28.0g of calcium chloride in enough water to make 225 mL of solution? Step 1: Find the number of moles of calcium chloride using n=m/M n= = = 0.252 mol CaCl 2 mMmM 28.0 110.98

4. Step 2: Use c=n/V to calculate the molar concentration c= = = 1.12 mol/L nVnV 0.252 0.225 L Notice the volume has been converted from mL to L

5. How many grams of sodium nitrate would be needed to make 425 mL of 6.00 mol/L solution? Step 1: Find the number of moles using n= cV n= (6.00 mol/L)(0.425L) = 2.55 mol of sodium nitrate Step 2: Calculate how many grams is needed using m = nM m = (2.55 mol) (85.00 g/mol) = 217 g of NaNO 3

6. Conversion of % to mol/L Calculate the concentration, in mol/L, of a 96% solution of sulphuric acid which has a density of 1.84 g/mL Step 1. Calculate the number of moles of sulphuric acid. N= m/M = = 0.98 mol of H 2 SO 4 96g 98.0 g/mol

7. Step 2: Find the volume of the solution using the mass and the density. Recall: V= m/D = = 54.3 mL = 0.0543 L of solution m D V 100 g 1.84 g/mL

8. Step 3: Calculate the concentration using c= n/V c = n/V = = 18 mol/L The concentration is 18 mol/L 0.98 mol of H 2 SO 4 0.0543L