Monthly Archives: February 2017

Before Class on Tuesday, Feb. 28

After reviewing the quiz we took last class, our new learning targets for Tuesday, Feb. 28 relate to buffers.   You should have picked up a packet of notes for buffers in class. If not they are here:   Buffer Notes .  We will discuss buffers before continuing our discussion of titrations.

After Feb. 28, you will be able to:

  • Describe the common ion effect;
  • Explain how a buffer functions;
  • Calculate the pH of a buffered solution;
  • Calculate the pH of a buffer after the addition of small amounts of a strong acid or a strong base.

Please watch the  4 videos below before Tuesday (12 min, 18 min, 14 min, 12 min.):

Intro to Buffers:

https://www.youtube.com/watch?v=cQZEZB2w3r4

Common Ions and Buffers: (18 min)

https://www.youtube.com/watch?v=RiTzZtQZDdc

Henderson Hasselbach and Buffers: (14 min)

https://www.youtube.com/watch?v=Jk9lRx8w4C0

Using Henderson Hasselbach to calculate pH: (12 min)

https://www.youtube.com/watch?v=qeHRmrxfx1Q

 

 

Before Class on Feb. 22

Our learning objectives for Wednesday are:

–Understand the relationship between Ka for a weak acid and Kb for its conjugate base.

–Describe the acid base properties of salts, and calculate the pH of a solution of a salt of a weak acid or a weak base

Before class on Feb. 22:

  • Please watch the video below (28 min);
  • Complete the notes; and
  • Make a comment.

https://www.youtube.com/watch?v=1-B8OOLPHtU

 

 

 

Before Class on

Before class on Feb. 17

  • Watch the two videos below (15 min. and 18 min.)
  • Complete the notes
  • Make a comment.

The learning objectives for class on Feb. 17 are:

–Calculate pKa from Ka (or Ka from pKa) and understand how pKa is correlated with acid strength.

–Understand the relationship between Ka for a weak acid and Kb for its conjugate base.

–Write equations for acid-base reactions, and decide whether they are product- or reactant-favored at equilibrium.

–Calculate the equilibrium constant for a weak acid (Ka) or a weak base (Kb) from experimental information (such as pH, [H3O+], or [OH–]

–Use the equilibrium constant and other information to calculate the pH of a solution of a weak acid or weak base.

–Describe the acid base properties of salts, and calculate the pH of a solution of a salt of a weak acid or a weak base

https://www.youtube.com/watch?v=ukQBSkx6lcw

 

https://www.youtube.com/watch?v=cs9q7TIZCAA

 

 

 

These are extra videos

These videos relate to the first few pages of Notes Packet 8.2.  The learning objectives they cover are:

  • Explain the difference between a strong and weak acid
  • Identify the 7 strong acids and the strong bases
  • Calculate the pH of a strong acid
  • Calculate K when given pH of a weak acid
  • Calculate pH when given K for a weak acid

I covered these notes in class, but if you were absent or want a review, here they are!

https://www.youtube.com/watch?v=mCSUz2vH5pY

 

https://www.youtube.com/watch?v=r09KdARPgnk

 

https://www.youtube.com/watch?v=GcNTO-t7InQ

Before class on Feb. 9

Sorry I did not post these videos earlier.  Our learning objectives for Feb. 9 are:

–Define and use the Bronsted concept of acids and bases.

–Recognize common acids and bases and write balanced equations for their ionization in water.

–Explain what it means to be amphiprotic

–Recognize a Bronsted acid or base in a reaction, and identify the conjugate partner of each.

–Use the water ionization constant, Kw.

–Use the pH concept.

 

Before class on Feb. 9

  • please watch the following 3 videos (21 min, 21 min, 11 min);
  • complete the notes;
  • and make a comment.

https://www.youtube.com/watch?v=sGzqjeESuPE

https://www.youtube.com/watch?v=GnNfhPk5z04

https://www.youtube.com/watch?v=h6Y3bw_MoY8

Before class on Feb. 7

Our learning objectives for Feb. 7 are to be able to:

  • explain Le Chatelier’s principle;
  • identify potential disturbances to a system at equilibrium; and
  • predict, using Le Chatelier’s principle, the effect of a disturbance on a chemical equilibrium.

Before class on Feb. 7:

  • please watch the video below (22 min.)
  • complete the notes
  • and make a comment.

https://www.youtube.com/watch?v=laawq0LkZZc

 

 

 

Before Class on Feb. 3

Our learning objectives for our next class are to:

  • be able to predict how a change in a system will affect the equilibrium concentrations, based on K;
  • Use K to predict equilibrium concentrations when only given initial concentrations.

Before class on Feb. 3:

  • Please watch the 2 videos below (7 min, 25 min)
  • Complete the notes
  • Make a comment.