Activity #7

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. There are 2 balloons in a room. They are identical in size and material. One balloon is filled with air and the other balloon is filled with Helium. How does the pressure of the air balloon compare to the pressure of the Helium balloon. The pressure in the air balloon is

     A. LessB. equal  C. greater

2. How does the pressure in the Helium balloon compare to the pressure of the air in the room? The pressure in the Helium balloon is 

     A. less  B. equal  C. greater

3.  How do the number of air molecules in the air balloon  compare to the number of He atoms in Helium balloon?
The number of air molecules is 

     A. less B. equal  C. greater

4. How does the average speed of the Helium molecules compare to that of the air molecules?
The average speed of the He molecules is

     A. less  B. equal  C. greater

5. What will happen to the pressure if temp is held constant and the volume is decreased? A.Pressure goes up because more collisions
B.Pressure goes up because more collisions are happening, but same force per collision
C.Pressure goes up because more collisions are happening, and increased force per collision
D.Nothing because pressure is only related to molecular speed

 6. You are flying from Denver to Boston, and you bring along a ½ full bottle of shampoo that was well sealed before you left Denver. You land in Boston and proceed to your hotel. The number of air molecules within the shampoo bottle:
A. has decreased B. has stayed the same
C. has increased

 

7. If the walls of the shampoo bottle are strong and rigid so that the bottle has the same shape as before you left, how does the pressure of the air inside the bottle compare to the pressure of the air in Denver?
         A.less than
B.equal to C.greater than

8. How does the pressure inside the bottle compare to the pressure of the air in Boston? A.less than
B.equal to
C.greater than

9. If you had a water bottle with very soft sides. When you open your suitcase in Boston, the bottle would look
A.squished
B.same size
C.puffed out
 

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.

	Strong Acid	Weak Acid	Strong Base	Weak Base	Water
pH meter read (value)	2.0	4.5	12.0	9.5	7.0
pH paper (color)	red	orange	blue	green	yellow
Conductivity (bright/dim/none)	bright	dim	bright	dim	very dim
Exists as Mostly (ions/molecules)	ions	molecules	ions	molecules	---

 

Conclusion Questions:

1.      A strong acid is very concentrated/ exists primarily as ions. (circle)

2.      A weak base is a nonelectrolyte / weak electrolyte / strong electrolyte.

3.      A strong base is a nonelectrolyte / weak electrolyte / strong electrolyte.

4.      At the same concentration (Molarity) a strong acid will have a higher / lower / the same pH as a weak acid.

5.      As concentration of a weak acid increases, the pH increases / decreases / remains constant.

6.      As concentration of a weak base increases, the pH increases / decreases / remains constant.

7.      As the concentration of a weak acid increases, the number of ions increases / decreases / remains constant.

8.      As the concentration of a weak acid increases, conductivity increases / decreases / remains constant.

9.      As the strength of a weak acid increases, the proportion of ions to molecules increases / decreases.

10.  As the strength of a weak acid increases, the conductivity increases / decreases / remains constant.

11.  What are the pH values of a weak acid with a concentration of 0.10 and a strong acid with a concentration of 0.01, ten times lower?     Weak acid, 0.10 M:4.0    Strong Acid, 0.01 M :2.0