Review Practice What is the molality of a solution created by adding 58 grams of magnesium hydroxide to 4 liters of water? Answer: 0.25 m Mg(OH)2 What is the molality of a solution created by adding 49 grams of sulfuric acid to 3 liters of water? Answer: 0.167 m H2SO4

Calculating Ion Concentration Write the dissociation equation. Determine the concentration of the solution. Use dimensional analysis and stoichiometry to determine ion concentration. Example: What is the hydrogen ion concentration if 2 moles of sulfuric acid are dissolved in 6 liters of solution? H2SO4 → 2H+ + SO42- 2 moles H2SO4 2 moles H+ = 0.67 M [H+] 6 L sol’n 1 moles H2SO4

Now you try What is the hydrogen ion concentration of a 3 liter solution with 24.5 grams of phosphoric acid? 0.25 M [H+] What is the hydroxide ion concentration of a 5 liter solution with 7.4 grams of calcium hydroxide? 0.04 M [OH-]

You try What is the hydrogen ion concentration of a 0.2 molar phosphoric acid solution? Answer: 0.6 M [H+] What is the hydroxide ion concentration of a solution made by adding 34 grams of calcium hydroxide to enough water to make 2 liters of solution? 0.5 M [OH-]

Acids and Bases Acids produce hydrogen ions when dissolved in water. HCl → H+ + Cl- Have a pH less than 7. Bases produce hydroxide ions when dissolved in water. Ca(OH)2 → Ca2+ + 2OH- Have a pH greater than 7 Pure water is neutral with a pH of 7

pH scale Scale used to show hydrogen ion concentration [H+] in a solution. pH scale ranges from 0-14. pH < 7 acidic pH > 7 basic pH = 7 neutral pH = -log [H+]

You Try Calculate the pH of the following hydrogen ion concentrations. 0.01 M [H+] 0.006 M [H+] 0.4 M [H+] 0.00008 M [H+]

More Calculate the pH of a 250 mL solution with 7.3 grams of hydrochloric acid. pH = 0.10 Calculate the pH of a 475 mL solution with 19.6 grams of sulfuric acid solution. pH = 0.075 Calculate the pH of a 1.6 Liter solution with 49 grams of phosphoric acid. pH = 0.028

pOH scale Scale used to show hydroxide ion concentration [OH-] in a solution. pOH scale ranges from 0-14. pOH > 7 acidic pOH < 7 basic pOH = 7 neutral pOH = -log [OH-] pH + pOH = 14 [OH-] = 10-pOH [H+] x [OH-] = 1 x 10-14

Practice What is the pOH of a 5 Liter solution with 148 grams calcium hydroxide solution? pOH = 0.10 basic What is the pOH of a 375 mL solution with .0316 grams of aluminum hydroxide? Is this solution acidic or basic? pOH = 2.50 basic What is the pH of a 50 mL solution with 0.00114 grams of magnesium hydroxide? Is this solution acidic or basic? pH = 10.9 basic