Catalyst – December log , 2.009x Which is a stronger acid, one with a pH of 5 or one with a pH of 3? 2. Which is a stronger base, one with a pH of 11 or one with a pH of 14? 3. Which is a stronger acid, one with a pH of 9 or one with a pH of 10?

Today’s Agenda  Catalyst  What’s a pirate’s favorite model of acid and bases?  ARR-Henius!  Now, calc it out, calc it out, calc it out  Reference sheet!  Practice  Progress Reports/Quizzes  Exit Question

Today’s Objectives  SWBAT calculate pH and pOH using known concentrations.

Arrhenius Model for Acids and Bases  Key Point #1: Arrhenius said… Acids will dissociate (separate) to produce hydrogen ions Bases will dissociate (separate) to produce hydroxide ions

Arrhenius Model for Acids and Bases  An Arrhenius acid is a substance that contains hydrogen and ionizes to produce hydrogen ions in aqueous solution HCl  H + + Cl -  A Arrhenius base is a substance that contains hydroxide and ionizes to produce hydroxide ions in aqueous solution NaOH  Na + + OH - This is called DISSOCIATION!

Practiccce…. Are these Arrhenius acids or bases? 1. HCl 2. Mg(OH) 2 3. H 2 SO 4 4. Ca(OH) 2 1. HNO 3 2. NaOH 3. H 2 CO 3 4. NH 4 OH

Concentration!  Now, we talked yesterday about how pH measures how ACIDIC or BASIC something is  It also shows us the STRENGTH of acids and bases  What do you think would make an acid STRONGER?  More H + or less H + ????  What do you think would happen to the pH?  IT WOULD DECREASE!

Concentration!  Now, we talked yesterday about how pH measures how ACIDIC or BASIC something is  It also shows us the STRENGTH of acids and bases  What do you think would make a base STRONGER?  More OH - or less OH - ????  What do you think would happen to the pH?  IT WOULD INCREASE!

How do we measure how much of something there is?  CONCENTRATION!  In chemistry terms, we call this MOLARITY.  Key Point #2: Concentration is measured in molarity and is used to calculate pH and pOH.

WHAAAAT THE HEEEECKK?  What’s pOH????!??!???!  Just like pH, which measures the hydrogen ions, pOH measures the hydroxide ions.  pOH is just used less commonly…  With pOH…  Acids > 7  Bases < 7

Ready to calculate?  Your equations are on the blue sheet, but you need to know when to use the right ones…  Let’s practice this skill first

How do you pick equations?  Find the equation where the thing that you are looking for is BY ITSELF and the thing that you have is in the equation!  What is the pH of a solution with 3.2 * M [H + ]?  What is the [OH - ] of a solution with a pOH of 12? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Let’s practice  Logarithims are functions that deal with exponents.  Unfortunately, we do not have time to deal with all the funness of logs- Algebra 2 will though!  What is the [H + ] of a solution that has a pH of 7?  [H+] = 10 -pH EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Let’s practice  What is the [H + ] of a solution that has a pH of 9? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Your turn  What is the [OH - ] of a solution with a pOH of 12.3? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Let’s practice  What’s the pOH of a solution with pH of 3? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Let’s practice  What’s the pH of a solution with a pOH of 6? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Your turn  What’s the pH of a solution that has 4.1 * M [H + ]? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Your turn  What’s the pH of a solution that has 1.0 * M [H + ]? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Your turn  What’s the pOH of a solution that has 3.4 * M [OH - ]? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Your turn  What’s the pOH of a solution that has 1.7 * M [OH - ]? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Tricksters…  What’s the pOH of a solution that has an [H + ] of 1.3 * M? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

Tricksters…  What’s the pH of a solution that has an [OH - ] of 2.2 * M? EQUATIONS! pH= -log [H + ] [H+] = 10 -pH pOH= -log [OH - ] [OH - ]= 10 -pOH pH+pOH=14

This is your time to shine…  Figure out those last problems on the homework!

Exit Question 1. If a solution has a [H + ] of.01, what is the pH of that solution? 2. What is the pOH of this solution?