Equilibrium - buffers Acid base equilibrium December 4, 2017 Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

December 4, 2017 Do Now (4 min) Learning target: I CAN define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases Do Now (Answer on your Do Now Sheet): Do Now (on the board): Predict the pH at each of the following points along a strong base weak acid titration, Ka = 10-5: 1) Only weak base present 2) A little strong base is added 3) At midpoint 4) At equivalence point 5) Excess base added Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

announcements December 4, 2017 Afterschool tutoring – every Wednesday 3 -4 PM Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

December 4, 2017 Buffers packet - pogil Work in pairs to complete each section of the packet 01 02 Get teacher approval at each STOP SIGN 03 Discuss and collaborate to understand how to solve more challenging problems 04 Show all work on your worksheets Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Exercise 6 part a-C (in pairs: 12 min) December 4, 2017 Exercise 6 part a-C (in pairs: 12 min) Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Ph Indicators! December 4, 2017 Color   pKIn pH range Acid Base Thymol Blue - 1st change red yellow 1.5 1.2 - 2.8 Methyl Orange 3.7 3.2 - 4.4 Bromocresol Green blue 4.7 3.8 - 5.4 Methyl Red 5.1 4.8 - 6.0 Bromothymol Blue 7.0 6.0 - 7.6 Phenol Red 7.9 6.8 - 8.4 Thymol Blue - 2nd change 8.9 8.0 - 9.6 Phenolphthalein colorless magenta 9.4 8.2 - 10.0 Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

December 4, 2017 Ph Indicators! At a low pH, a weak acid indicator is almost entirely in the HIn form, the color of which predominates. As the pH increases, the intensity of the color of HIn decreases and the equilibrium is pushed to the right.  Therefore, the intensity of the color of In- increases.  An indicator is most effective if the color change is distinct and over a small pH range.  For most indicators the range is within ±1 of the pKln value. Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Exercise 7 (in pairs: 8 min) December 4, 2017 Exercise 7 (in pairs: 8 min) Kb = 1.8 x 10-5 Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Exercise 8 (in pairs: 12 min) December 4, 2017 Exercise 8 (in pairs: 12 min) Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Video (11 Min) December 4, 2017 Take Notes Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Titration curves December 4, 2017 Adding base to acid Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Titration curves December 4, 2017 Adding acid to base Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

Titration curves (15 min) December 4, 2017 Titration curves (15 min) Practice questions 42 – 46 in pairs Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases

December 4, 2017 Exit ticket (3 min) On a separate sheet of paper: What is a buffer? What is it used for? Learning Target: I CAN Define a buffer system and calculate pH and determine the changes in pH based on Ka and concentration of acids and bases