5/2/11: Turn in science fair ideas if you have them, please sit in new seats, check your grade as of 4/28

Objective: Describe the properties of acids and bases

Catalyst (on paper today, leave room for an “exit slip”):For the following questions, use your prior knowledge. Do not worry if your answers are “right”1.List everything you know about acids.2.List everything you know about bases.3.Which would you prefer to drink, a strong acid or a strong base-why?

Homework: Read pages 530-538 and answer questions 1-5 on page 538 (due Wednesday)

Acids & BasesAcids & BasesAcids & BasesAcids & Bases

Some Properties of Acids Produce H+ (as H3O+) ions in water (the hydronium

ion is a hydrogen ion attached to a water molecule)

Taste sour

Corrode metals

Electrolytes

React with bases to form a salt and water

pH is less than 7

Turns blue litmus paper to red

•HBr HBr (aq)(aq)

•HH22COCO33

•HH22SOSO33

hydrobromic acidhydrobromic acid

carbonic carbonic

acidacid

sulfurous sulfurous

acidacid

Acid Nomenclature Review

Name Them!

• HCl HCl (aq)(aq)

• HH22SOSO44

• HNOHNO33

Hydrochloric acid

Sulfuric Acid

Nitric Acid

Some Properties of Bases

Produce OHProduce OH-- ions in water ions in water

Taste bitter, chalkyTaste bitter, chalky

Are electrolytesAre electrolytes

Feel soapy, slipperyFeel soapy, slippery

React with acids to form salts and waterReact with acids to form salts and water

pH greater than 7pH greater than 7

Turns red litmus paper to blue “Basic Turns red litmus paper to blue “Basic

Blue”Blue”

Some Common Bases

NaOHNaOH sodium hydroxidesodium hydroxide lyelye

KOHKOH potassium hydroxidepotassium hydroxide liquid soapliquid soap

Ba(OH)Ba(OH)22 barium hydroxidebarium hydroxide stabilizer for stabilizer for

plasticsplastics

Mg(OH)Mg(OH)22 magnesium hydroxidemagnesium hydroxide Milk of Milk of

magnesiamagnesia

Al(OH)Al(OH)33 aluminum hydroxidealuminum hydroxide Maalox (antacid)Maalox (antacid)

The pH scale is a way of The pH scale is a way of expressing the strength expressing the strength of acids and bases. of acids and bases. Instead of using very Instead of using very small numbers, we just small numbers, we just use the NEGATIVE power use the NEGATIVE power of 10 on the Molarity of of 10 on the Molarity of the Hthe H++ (or OH (or OH--) ion.) ion.

Under 7 = acidUnder 7 = acid 7 = neutral 7 = neutral

Over 7 = baseOver 7 = base

pH of Common pH of Common SubstancesSubstances

After today’s lesson, answer the following questions again…1.List everything you know about acids.2.List everything you know about bases.3.Which would you prefer to drink, a strong acid or a strong base-why?

5/3/11:Objective: Describe how pH can be found from the amount of H+ in solution.

Catalyst:Why is scientific notation useful?Write the following numbers in regular notation:1.3 X 10-47.6 X 10-74.22 X 10-6

Homework: Read pages 530-538 and answer questions 1-5 on page 538 (due Wednesday)

Molarity Concentration

In order to determine the concentration of a solution, simply take the number of moles of solute divided by the Liters of solution.

M = Moles of solute Liters of solution

Example• If a 2 mole solution of NaCl were

dissolved in 4 L of solution, what would be the concentration of NaCl?

Answer: 2 mole NaCl = 0.5 M NaCl4 L of solution

Calculating the pHpH = - log [H+]

(Remember that the [ ] means Molarity)

Example: If [H+] = 1 X 10-10

pH = - log 1 X 10-10

pH = - (- 10)pH = 10

Example: If [H+] = 1.8 X 10-5

pH = - log 1.8 X 10-5

pH = - (- 4.74)pH = 4.74

pH calculations – Solving for H+pH calculations – Solving for H+What is the pH of a solution with What is the pH of a solution with

a concentration of 1.0 x 10a concentration of 1.0 x 106 6 M.M.

pH = - log [HpH = - log [H++]]

pH = - log [1.0 x 10pH = - log [1.0 x 10 6 6 M] M]

pH = 6pH = 6

pH = - log [HpH = - log [H++]]

pH = - log [1.0 x 10pH = - log [1.0 x 10 6 6 M] M]

pH = 6pH = 6

Let’s Practice

• Find the pH of the following solutions.

1. 1.0 x 10 -13 M2. 1.0 x 10 -2 M3. 2.4 x 10-5 M (log = -4.6)4. 8.6 x 10 -11 M (log= -10.1)

Estimate pH:A. 6.3 x 10 -11 MB. 1.3 x 10 -4 MC. 1.2 x 10-6 M D. 4.3 x 10 -9 MDetermine whether solution is an acid or base:A. 7.1 x 10 -3 MB. 4.3 x 10 -13 MC. 9.2 x 10-10 M D. 1.4 MThen, order all letters from most acidic to

most basic