1. If rainwater is completely unpolluted, what substances are found dissolved in it?
2. If people have been polluting the air, what does that do to the rainwater?
3. What dissolves into the rainwater once it strikes the Earth?
4. Name the three basic steps in nature's water purification system.
5. If the groundwater is slightly acidic, what metal ions may dissolve into the water?
6. Why is hard water called hard water?
7. What is the formula for sodium hexametaphosphate?
8. Does river water usually contain a high concentration of hard-water ions?
9. According to the map on page 67, what's the approximate hardness of the water in Maine?
10. What are two household problems caused by hard water?
11. What's the chemical formula for...
(a) gypsum?
(b) limestone?
12. What was the problem with most of the first detergents that were invented?
Questions? Comments??
Bob Clark