Activity 7

Activity 7: Acids and Bases

1. The color of a solution identifies if it is an acid, base, or neutral solution. True or False

False.  The pH determines whether it is a base or acid. A pH that is above 7 is a base and below 7 is an acid. A 7 would yield a neutral solution.  The color of the solution does not determine whether it is a acid, base, or neutral solution.

2. Which solution is basic?

More than one. Solution B and C are both above 7 so they are basic.

3. Which solution is acidic?

C is the solution that is acidic.  The high level of H3O+ in C tells us that C is acidic.

4. Which solution is basic?

B is the solution that is basic.  A is neutral coming in at 7 on H3O+ and OH-.  B is basic with OH- at -2.  C is acidic with H3O+ at -3.

5. Which solution is acidic?

A & B.  H3O+ for both A and B high enough to be acidic.  10^16 is neutral and both of these are higher than that.

6. How will adding water effect the pH?

A.Increase the pH. Adding water with a pH of 7 will add to the pH level of 5 since the pH level of water is higher than the starting pH. It takes away from the acidity of the starting solution to make it more basic.

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

Starting Solution with pH of 10 with end solution of ph of 9.71 after equal water added

B.Decrease the pH. The pH of the solution is higher than that of the water so it will decrease the pH of the solution.  The solution is pH of 10 and water is a pH of 7. Adding an equal amount of water will bring the pH of the solution down to around 9.71.

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

A. A B C. The lower the pH the higher the acidity.  The higher the pH the more basic it is. The order from smallest to largest is A, B, C.

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

E. C A B.  The higher the bar on the graph for the H3O+ the more acidic the solution is.  The order from highest to lowest is C, A B.

10. If spit has a pH = 7.4, what does that tell you about the water equilibrium?

A. Something was added that made the equilibrium shift left

·         Begin with a strong acid and lower the pH probe into the beaker.  What is the pH of this solution? 

·         Test this strong acid with both pH paper and the conductivity probe.  What color does the pH indicator become?  Is this strong acid an electrolyte?  Does current travel through this solution?

·         Repeat the above tests with the weak acid, the strong base, and the weak base, and water.  Collect your observations in the table below:

 

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.