Acids and Bases

pH Scale

Apply the Numbers

NOTE [ BRACKETS ] = CONCENTRATION (MOLARITY)

Determining Strength Dissociation: compound breaking into ions HCl  H + Cl -

Determining Strength [H+] or [H 3 O+] = Acidic Strength [OH-] = Basic Strength

Using Water to Determine Strength K w = [H+] x [OH-] = 1.0x Reference table!!!!!!!!!

Determining Strength We use the concentrations to determine if a solution is acidic or basic. Careful, since we are using a negative coefficient. The larger the coefficient = the smaller number. (this’ll make sense shortly)

Always get to this if confused

Cokes are slightly acidic, if the [H+] in a solution is 1x10^5 M, is the solution acidic, basic, neutral? What is the [OH-] of the solution?

Is a [H+] = 6.0x10^-10 M solution acidic, basic, or neutral? (think logically, not # crunching)

Crunching Molarity and Kw can be complicated. pH

[H+] pH = -log [H+ ] Ref table

[OH-] pOH = -log[OH-] Ref table

What iF I gave you a hydroxide concentration and asked for pH pH + pOH = 14 Ref table

What is the [OH-] from a solution with a pH of 4.5?

What is the pH of a solution with a pOH of 3.2?

What is the pOH of a solution with [H+] = 3.5x10^-8 M

Acid Dissociation HCl --> H + and Cl -1-

Sour Taste React with metals Turn litmus paper RED 3 Properties of Acids

Acid Examples

Bases

Bases end in “OH” (hydroxide)  NaOH  KOH  Mg(OH) 2

BASES Break into (OH) - ions

Base Dissociation Mg(OH) 2 --> Mg +2 and (OH) -

Properties of Bases Bitter taste Slippery feel (like soap) Turn litmus paper BLUE

Acid + Base Acid + Base --> Water + Salt

pHpH

What is pH pH measures how ACIDIC (H) + a solution is

Every solution has both acidic (H) + and basic (OH) - ions in it, whichever ions have more will tell us the type of solution

The pH scale 0 --> 14 Color your pH scale according to the following slide

Neutral pH 7.0 Pure Water

Base pH Level pH greater than 7.0

Base pH Strength (common sense) Higher = Stronger

pH 12 stronger base than pH 9

Acids pH Levels pH below 7.0

Acid pH Strength (Reverse of common sense) Lower Number = Stronger

pH 1 is stronger acid than pH 5

How much does strength increase or decrease? Moving up/down on pH scale is by a factor of 10x

Compare pH of 4 to a pH of 5 Acidic pH of 4 is 10x more acidic than pH of 5 Basic pH of 5 is 10x more basic than pH of 4

Compare pH 9 to pH 12 Acidic pH 9 is 1000x more acidic (10x10x10) than pH 12 Basic pH 12 is 1000x more basic than pH 9

pH=0 Strongly Acidic pH=7 neutral pH=14 Strongly basic

What substance would you use to neutralize an acid with a pH of 1.5? A. Milk C. Ammonia B. Vinegar D. Water

Neutralization To neutralize a solution ADD Opposite! Add base to neutralize an acid Add acid to neutralize a base

Easy step Neutralizing pH calculation find neutralizing pH 14 – pH given = pH needed to neutralize

What pH would neutralize a stomach acid (ph of 2)

Pepto Bismol vs Milk of Magnesia pH ~6.0 pH ~10.0 Which would be better? Think about it!

Give dissociation of calcium hydroxide

pOH is 11.64, and you have 2.55L of solution, how many grams of Calcium hydroxide are in solution?

1.5L of solution containing 5.6 g of hydroiodic acid, what is the pH