1. Solutions: Concentrations

2. What is Molarity?
Unit of concentration (how much solute is dissolved into the solvent)
Expresses concentration quantitatively
Aka: molar concentration

3. How is it calculated? Molarity (M) =
3 M NaCl is read as “3 molar sodium chloride”

4. Guided Practice Problem
IV saline solutions are often administered to patients in the hospital. One saline solution contains 0.90 g NaCl in exactly 100 mL of solution. What is the molarity of the solution?
Change mL of solution into L (if necessary):
100 mL x = 0.1 L
Change g to mol (if necessary):
0.90 g x = mol NaCl
Divide mol solute by L solution:
= 0.15 mol/L = 0.15 M solution

5. 2. What is the molarity of 38.9 g of CaCl2 dissolved in water to make a 0.78L solution?

6. 3. How many grams of potassium iodide are needed to make 500 mL of a 6
3. How many grams of potassium iodide are needed to make 500 mL of a 6.5 M KI solution?

7. 4. When preparing a stock 4 M HCl solution, 291. 68 g of HCl were used
4. When preparing a stock 4 M HCl solution, g of HCl were used. What is the volume of the resulting solution?