You are INITIALLY given 98.5 grams of Magnesium Hydroxide, Mg(OH)2, in a 500 mL solution with water. Kb = 8.9x10-3

1. Is magnesium hydroxide a weak or strong base?

2. What is the concentration of Mg(OH)2? 3. What is the [OH-]? [YOU NEED ICE

TABLE] 4. What is the pH of this substance?

Warm Up #7

Warm Up #7

10 grams NH3, a weak base, reacts with water to make a 5 L solution at equilibrium. The

Kb of NH3 is 1.8x10-5

Calculate [NH3]…M = mol/L

Show the reaction between NH3 and water, and set up a Kb equation.

Solve for the [OH-]. With this, solve for the pH of your base.

CHAPTER 19.5

Hydrolysis of a Salt

Hydrolysis…what?

Hydrolysis – adding water

When adding water to a salt you get… One acid One base

Ex. NaCl + HOH NaOH + HCl NaOH = base, HCl = acid DOUBLE REPLACEMENT

Strong Acids and Bases

Strong Acids: HCl, HBr, HI, HNO3, HClO3, H2SO4

Strong Bases: Any Alkali/alkaline metal with OH (except Mg)

pH of the Salts

Strong acid and Strong base NEUTRAL pH

Strong acid and Weak base ACIDIC pH

Weak acid and Strong base BASIC pH

Weak acid and Weak base UNKNOWN pH

Warm Up #9

You add water to Al(NO3)3:

Show this chemical reaction, and balance the equation.

On the products side, label the acid and the base (including their names). Also, include the strength of each (weak/strong).

What will the pH of this salt be (acidic/basic)? How do you know?