Solutions and Concentrations Notes Page 5

SOLUTIONS A homogenous mixture of two or more substances

2 PARTS OF A SOLUTION SOLUTE A solute is the dissolved substance in a solution. Sugar in soda Carbon dioxide in soda Salt in salt water SOLVENT A solvent is the dissolving medium in a solution. Water in salt water Water in soda

Molarity = concentration Amount of substance (mol) Volume of mixture (L) Unit = mol/L or M 1.0 M = 1 molar 12.0 M = 12 molar

solUTE over solVENT

Example mol of NaCl are dissolved in 1 L of water. What is the molarity of the solution? 1.5 mol NaCl = 1.5 mol/L or 1.5 M 1 L H 2 O

Example g of NaCl are dissolved in 1 L of water. What is the molarity of the solution? 100 g NaCl |1 mol NaCl = 1.71 mol g NaCl 1.71 mol NaCl = 1.71 M 1 L

Example g of NaCl are dissolved in 250 mL of water. What is the molarity of the solution? 100 g NaCl |1 mol NaCl = 1.71mol g NaCl 250 mL / 10 3 mL = 0.25 L 1.71 mol NaCl = 6.84 M 0.25 L

Example 4 How many moles of NaCl are in 500 mL of a 0.25 M solution? Basic formula: M = mol L Convert: 500 mL = 0.5 L 0.25 M = mol = 0.5 L x 0.25 M = mol 0.5 L = mol NaCl

Example 5 How many grams of NaCl are in 500 mL of a 2.25 M solution? Basic formula: M = mol L Convert: 500 mL = 0.5 L 2.25 M = mol = 0.5 L x 2.25 M = mol 0.5 L = mol NaCl mol NaCl | g NaCl = g NaCl 1 mol