Acids and Bases 5 Boon Chemistry January 24 & 25, 2013

Catalyst Think back to the investigations you completed this week. When a person takes Tums (or another antacid) what happens to the pH in their stomach? Why?  Objectives  I can demonstrate my knowledge of acid/base chemistry on the Unit 7 exam.  Objectives  I can demonstrate my knowledge of acid/base chemistry on the Unit 7 exam.  Agenda  Catalyst and Homework Review  Unit 7 Exam  Flashcards: Thermochemistry  Agenda  Catalyst and Homework Review  Unit 7 Exam  Flashcards: Thermochemistry  Take out your homework please.

Exit Slip: Answers Standard IE 1e/5d  What is the [H 3 O + ] in a M solution of NaOH (a strong base)?  (a) 2.5 x M(c) 4.0 x M  (b) 2.5 x M(d) 1.0 x M  Why? 1.0 x = [H 3 O + ] (4.0 x ) Solve by dividing.  As the [H 3 O + ] of a solution increases, the value of  (a) log [H 3 O + ] increases.(c) the solution’s pH decreases.  (b) –log[H 3 O + ] decreases.(d) all of the above  Why? Test each answer. They are all true.  What is the [OH - ] in a sample of lime juice with a pH of 2.0?  (a) 1.0 x M(c) 1.0 x M  (b) 1.0 x M(d) 1.0 x M  Why? Read carefully. If pH is 2, then pOH is 12. This corresponds to 1.0 x M

Exit Slip answers continued (4) If the pH of a solution is increased from 2.0 to 4.0, the [H 3 O + ] concentration (a) decreases by a factor of 2. (b) decreases by a factor of 100. (c) increases by a factor of 3. (d) increases by a factor of Why? As pH goes up, [H 3 O + ] goes down. Each time you move one space on the pH scale you are changing the [H 3 O + ] by a factor of 10. Moving 2 spaces is 10x10=100. (5) What is the pH of household ammonia in which the [H 3 O + ] is 1.0 x M? (a) 2(c) 10 (b) 7(d) 12 Why? corresponds to pH=12. pH = -log[H 3 O + ]

Homework Review page , [H3O+] = 5.0 x M pH = -log[H3O+] pH = -log[5.0 x ] pH = [H3O+] = 0.2 M pH = -log[H3O+] pH = -log[2.0 x ] pH = [OH-] = 2.0 x pOH = -log[OH-] pOH = -log[2.0 x ] pOH = 2.7pOH + pH = 14; pH = [OH-] = 0.35 M pOH = -log[0.35]pOH = 0.45 pOH + pH = 14 pH = 13.55

Homework Review page , pH = 3.3 [H3O+] = 10 -pH [H3O+] = [H3O+] = 5.0 x pH = 11.7; pOH = = 2.3 [OH-] = 10 -pOH = = 5.0 x pH = 8.1; pOH = = 5.9 [H3O+] = = 7.9 x [OH-] = = 1.3 x pH = 7.67; pOH = = 6.33 [OH-] = = 4.7 x This is outside the normal range, the patient should be concerned.

Acid/Base Exam  Expectations/Instructions:  Work independently and silently.  Write on your test.  Be sure to answer every question. There are multiple choice and short answer.  The Tools:  Use your pH foldable worksheet.  Use your own calculator.  If you finish early:  Turn in your test and all your pH worksheets, handouts, etc.  Begin the flashcard assignment for Unit 8.

Thermochemistry Flashcards  Front of card:  Vocabulary word  Picture/diagram  Back of card:  definition  Sentence using the word  Resources:  Textbook Glossary  Words are also posted on the wall.  Words  Endothermic  Exothermic  Melting point  Boiling point  Freezing point  Condensation  Fusion  vaporization  Sublimation  Evaporation  Heat  Temperature  Energy  Enthalpy  Entropy  Joule  Specific heat  calorie

Homework  Due Next Class: Complete your flashcards