Strengths of Acids and Bases

Name: ______Date: ______Period: _____

The pH values of several common substances are listed below. Place each item from the list on the pH scale in its proper location. One has already been done for you.

8.5 – ocean water 2.5 – lemons 10.5 – milk of magnesia 4.0 – tomatoes 5.8 – shampoo 11.5 – ammonia 13.8 – lye 5.2 – bananas 7.8 – eggs 1.0 – stomach acid 7.2 – blood 10.0 – soap 3.0 – vinegar 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Complete the table below by writing the name of each of the substances above under the proper heading in the table. Place substances with a pH lower than 3.0 in the strong acids column. Place substances with a pH higher than 10.0 in the strong bases column. Strong Acids Weak Acids Weak Bases Strong Bases < 3.0 > 3.0 < 10.0 > 10.0

Answer the following questions on the lines provided. 1. Is pure water an acidic, basic, or neutral substance? ______2. Strong bases have a pH greater than ______. 3. Strong acids have a pH lower than ______.

Unit 2, Section 1a, Page 5 Maintaining Homeostasis

Homeostasis – the ability of an organism to regulate their internal environment regardless of changes in the external environment.

A major problem for animals that live in or around water is acid rain. Acid rain is rainwater with a pH lower than 7.0 because of the burning of fossil fuels from cars, the production of electricity, factories, etc. Each whole number jump in pH is 10x greater or weaker depending on the direction.

Answer the following questions to help you review pH. 1. Define acid - ______2. Define base - ______3. An _____ is an atom that has gained or lost an electron and has become charged. 4. Where does the increased acidity come from in many of our lakes and streams? ______

The following is a list of animals that are affected by lowering pH levels in our streams and lakes. Place the name of each animal of the pH scale when it dies out. mayfly – 5.0 crayfish – 5.0 snail – 5.5 rainbow trout – 5.0 brown trout – 4.5 brook trout – 4.0 bullfrog – 4.0 fathead minnow – 5.5 pumpkinseed sunfish – 4.5 yellow perch – 4.0 wood frog – 3.5 small mouth bass – 5.0 American toad – 4.0 clam – 5.5 spotted salamander – 4.5 3 3.5 4 4.5 5 5.5 6

5. What is the lowest pH level where an aquatic animal can survive? ______6. Which animal is the last to die off? ______7. What 3 animals die at the highest pH? ______8. How many times lower is a pH of 3.5 compared to a pH of 5.5? ______

Unit 2, Section 1a, Page 6 9. Is 3.5 a stronger or weaker acid that a pH of 5.5? ______

Unit 2, Section 1a, Page 7