Environmental pH

NameJ _________________

DateJ   _________________

 

Introduction:  A liquid may be an acid, base, or neutral.  The degree of acidity or basicity can be measured by using the pH scale.  The scale is divided into three areas:  Acid (readings below 7), neutral (reading of 7), and basic (readings above 7).  Each division either increases or decreases the pH of a substance 10 times.  The pH of 5 is ten times more acidic than a pH of 6.  Water has a pH of 7 but when it mixes with air the suspended materials will either raise or lower its pH.  Acid Rain is an example of this type of reaction.

 

Objective:

 The students will determine the pH of various substances and will determine how some of these substances can affect the environment.

 

Materials:

            Litmus paper and Chart                Forceps

            Masking Tape                                      Paper Towels

            10 depression slides                            Lemon Juice

            Cola                                                     Ammonia

            Detergent                                             Pond Water

            Distilled Water                           Salt Water

            Tap Water                                       Baking Soda

 

Procedure:

            Using a tape label 9 depression slides A-JI.

Put a drop of liquid on each slide as listed below: Caution do not come in contact any of the materials.  If contact is made wash it off and notify the instructor.

Slide A-Lemon Juice, Slide B-Distilled Water, Slide C-Pond Water, Slide D-Tap Water, Slide E-Salt Water, Slide F-Ammonia, Slide G-Baking Soda, Slide H-Cola

Slide I-Detergent, Slide J-UNKNOWN

Pick up a piece of pH paper with the forceps

Hypothesize whether the liquid will be acid or base

Record this data below

Touch the pH paper to the liquid in slide A and remove it.  Compare the color of                        paper with that on the pH chart.

Record your observations

Repeat the procedure with the rest of the slides

 

 

 

 

 

 

Slide

Hypothesis

pH

Acidic

Basic

Neutral

A

 

 

 

 

 

B

 

 

 

 

 

C

 

 

 

 

 

D

 

 

 

 

 

E

 

 

 

 

 

F

 

 

 

 

 

G

 

 

 

 

 

H

 

 

 

 

 

I

 

 

 

 

 

J

 

 

 

 

 

 

Analysis:

 

1)  Which of the liquids had the lowest pH?

 

 

2)  Which of the liquids had the highest pH?

 

 

3)  Which of the liquids were closest to being neutral?

 

 

4) If the pH of a sample was 3 how many more times acidic is it than a solution with a pH of 6?

 

 

 

5)  How might one correct the pH of a lake with a reading of 3?

 

 

 

 

6) What is the pH of human skin?

 

7)  How does non-tearing shampoo work?

 

 

 

8)  What is the pH of rain water?

 

 

9)  What local industries pump materials into the atmosphere to create a drastic change in the rain what?