Unit 1 SCS #9-19 (pg. 82-83)

9. 20% of 55 = 11                    55 – 11 = 44

    11 grams of sugar                44 grams of water

10. 1.5 parts per million (ppm)

11. A water molecule is polar because one end of the molecule is negative (oxygen) and the other end is positive (hydrogen).

12.

13. a. Oxygen molecules

      b. Hydrogen molecules

14. Heavy metals are called “heavy” because their atoms have a greater mass than those of metallic elements.

15. Some symptoms of heavy metal poisoning are numbness, staggered walk, tunnel vision, and brain damage.

16. a. Before the 1970’s, a molecular compound containing lead was added to gasoline to produce a better-burning automobile fuel but the lead entered the atmosphere and sunk into soil near the road.

      b. In the 1700’s and 1800’s mercury nitrate was used in making felt hats so the hat makers were exposed to the mercury, which absorbed through their skin giving them “mad hatter” poisoning.

17. Hydroxide is a very common ion found in many bases.

18. Hydrogen is a common element found in acids.

19. a. basic

      b. basic

      c. acid

      d. chemically neutral