Activity 7: Acids and Bases

Water is everywhere!  So, lets spend one more activity learning about one of the key aspects of water.  Water has the ability to dissociate (break apart from HOH (or H₂O) into H+ ions and OH- ions).  We refer to solutions with lots of H+ ions as acids and solutions with lots of OH- ions as bases.  By adding chemicals with H+ ions acidic solutions can be made.  By adding chemicals with OH- ions basic solutions can be made.

Activity Tasks:

1. Review the Content Slides Acids and Bases on the D2L site.

2. Complete the Teaching Idea “Concept Questions for Chemistry using PhET”  posted by Trish Loeblein on the pH Scale simulation at PHET (http://phet.colorado.edu/en/simulation/ph-scale). On your blog post the answers with your scientific explanations from the “Clicker Questions pH Scale” posted by Trish.

1. The color of a solution identifies if it is an acid, base, or neutral solution.
1. B. False, because color of a solution does not not mean if it is an acid, base, or neutral solution; the color and number on the pH scale do determine if it is an acid, base, or neutral. 
2. Which solution is basic?
1. D. More than one, because two have a pH level of 7.01 or above.
3. Which solution is acidic?
1. C. There is a very high H3O+ level and a low OH- level.
4. Which solution is basic?
1. B. There is a very high OH- level in comparison to H3O+ level.
5. Which solution is acidic?
1. D. More than one, Both A and B are acidic because they have higher levels of H3O+
6. How will adding water effect the pH?
1. A. Increase the pH, because more water lessens the acidity to solution ratio.
7. How will equal amount of water effect the pH?
1. B. Decrease the pH, because there is less water to dilute the solution, the acidity is higher so the pH level decreases.
8. What is the order from most acidic to most basic?
1. A. ABC, the lower the pH level, the more acidic the solution.
9. What is the order from most acidic to most basic?
1. E. CAB, the higher level of H3O+ in comparison to OH-, the greater the acidic.
10. If spit has a pH = 7.4, what does that tell you about the water equilibrium?
1. A, because the pH was not 7 and more H3O+ was added to make it shift left.

3. Complete the Teaching Idea “Intro to Strong and Weak Acids and Bases” posted by Chris Bires on the Acid-Base Solutions simulation (http://phet.colorado.edu/en/simulation/acid-base-solutions) and post on your blog your data and answers to the questions posed.