Activity #7

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:

 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.*** (Slides 146 through 157)
ANSWER:
1. The color of a solution identifies if it is an acid, base, or neutral solution.

B. The color does not tell whether the solution is an acid or a base.

2. Which solution is basic?

D. More than one of the solutions has a pH above 7, therefore both B and C are basic.

3. Which solution is acid?

C. The amount of Hydrogen atoms is more in this solution

4. Which solution is basic?

B. The lower amount of Hydrogen atoms versus hydroxide makes this a basic solution. 

5. Which solution is acidic?

D. Both A and B have a pH level that is below 7, making them acidic.

6. How will adding water effect the pH?

A. Increase the pH- more water will lessen the acidity, and the pH goes up.

7. How will equal amount of water effect the pH?

B. Decrease the pH because more water lessens the base, so the pH will go down. 

8. What is the order from most acidic to most basic?

A. A= 6.50, B= 7.40, and C= 12.06

9. What is the order from most acidic to most basic?

C. B, A, C

10. If spit has a ph = 7.4, what does that tell you about the water equilibrium?
2H2O<-> OH- +H3O+

ANSWER: A. Something was added that made the equilibrium 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.