Arrhenius acid - any HA, H 2 A, H 3 A, or RCOOH substance with an H + to donate Examples include HCl, H 2 SO 4, H 3 PO 4, and CH 3 COOH

Arrhenius base - any MOH, M(OH) 2, or M(OH) 3 substance with an OH - to donate Examples include NaOH, Ca(OH) 2, and Fe(OH) 3

Acids and bases react with one another in NEUTRALIZATION reactions which produce water and a salt. HA + MOH --> HOH + MA

What volume of 0.25 M phosphoric acid is needed to titrate 50 mL of 0.35 M barium hydroxide? First, let’s write a balanced equation to relate the two chemicals that are involved.

2H 3 PO 4 + 3Ba(OH) 2 --> 6H 2 O + Ba 3 (PO 4 ) 2 We know more about the barium hydroxide so we’ll begin with the volume and molarity for the stoichiometry.

0.05 L Ba(OH) 2 (0.35 mol Ba(OH) 2 )(2 mol H 3 PO 4 )(1 L H 3 PO 4 ) 1 L Ba(OH) 2 3 mol Ba(OH) mol H 3 PO 4 = 0.47 L H 3 PO 4 Titration is a lab technique that involves reacting one substance of a known molarity with one of unknown concentration in order to determine the unknown.

This problem is EXACTLY the solution stoichiometry from the previous unit. The only thing that’s new is the word TITRATE.

Some acids are STRONG. This means that they dissociate completely to give H + ions and anions. HCl ---> H + + Cl -

There are 6 strong acids. They are HCl, HBr, HI, HNO 3, HClO 4, and H 2 SO 4. Because STRONG species ionize completely, we can easily find pH for them.

There are certain bases which are STRONG. They are the alkali metal hydroxides AND Ca(OH) 2, Sr(OH) 2, and Ba(OH) 2. Being STRONG means they dissociate 100%.

You will see [ ] used in this unit. The [ ] mean equilibrium concentration (molarity). For a strong species, the [ ] will be easy to discern.

pH is a measure of the acidity or basicity of a solution. Note the H is capitalized. Why? Mathematically, we can find pH = - log [H + ] Your calculator will do this for you easily.

What is the pH of a 0.3 M solution of HNO 3 ? HNO 3 is a strong acid so we can find the pH readily. [HNO 3 ] = [H + ] because HNO 3 --> H + + NO 3 -

pH = - log [H + ] pH = - log (0.3 M) pH = 0.52 pH does not have units but what does it mean?

If pH 7, then your solution is BASIC.

Acids are substances that: react with metals to produce H 2 cause blue litmus to turn red taste sour have H+ ions

Bases are substances that: cause red litmus to turn blue taste bitter feel slippery have OH- ions

There are 4 equations that work together to solve problems. pH = - log [H + ] pOH = -log [OH - ] pH + pOH = 14 [H + ][OH - ] = 1 x = Kw

What is the pH, the pOH, the [H+], and the [OH-] of a solution of 0.25 M Ca(OH)2? Since Ca(OH)2 is a STRONG base, it dissociates completely.

Ca(OH) 2 --> Ca OH - What will the [OH - ] be? Since there are 2 hydroxides for every one Ca(OH) 2, the hydroxide molarity is 0.5 M.

pOH = -log [OH - ] pOH = -log (0.5M) pOH = 0.3 pH + pOH = 14 pH = 14 - pOH pH = pH = 13.7 > 7 therefore basic

[H + ][OH - ] = 1 x [H + ](0.5M) = 1 x [H + ](0.5M) = 1 x M0.5 M [H + ] = 2 x M

Every other acid is a weak acid and ionizes partially to produce H+ ions in solution. HC 2 H 3 O 2 H + + C 2 H 3 O 2 -

Notice the double-headed set of arrows? This means the reaction is at equilibrium. The forward equation occurs at the same time and same rate of speed as the reverse reaction.

Weak acids and weak bases do not dissociate completely. They exist in equilibrium with their ions. This means that finding pH becomes more challenging for weak species.