1. Acids and Bases

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

3. Calculating Ion Concentration
Write the dissociation equation.
Determine the molarity of the solution.
Multiply the Molarity of the solution by the number of Hydrogen or Hydroxide Ions in the Compound.
Example:
What is the hydrogen ion concentration if 2 moles of sulfuric acid are dissolved in 6 liters of solution?
H2SO4 → 2H+ + SO42-
M = 2mol/6L = 0.33 M
0.33 M x 2H+= 0.67 M [H+]

4. 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-]

5. 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

6. 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+]

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

8. 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

9. 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

10. 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 grams of aluminum hydroxide? Is this solution acidic or basic?
pOH = 2.50 basic
What is the pH of a 50 mL solution with grams of magnesium hydroxide? Is this solution acidic or basic?
pH = 10.9 basic