1SCS #9-27, 33, 35

9. 20% of 55 =11 grams (mass of the sugar) --> 55-11= 44 grams (mass of the water)

10. 0.0015 x 1,000,000 = 1500 ppm

11. Water molecules are polar due to electrically negative oxygen at the end of the water molecule and positive hydrogen at the end. This is because oxygen is more electronegative than hydrogen. Electrons are partially pulled away from the two hydrogen atoms, and toward the oxygen atom.

12.

13. A. O-
      B. H+

14. Heavy metals are called "heavy" because their atoms have greater masses than those of essential metallic elements.

15. Three symptoms of heavy metal poisoning are damage to the nervous system, brain, kidneys. More symptoms may include liver damage and death.

16. Sources of human exposure to lead may be from some homes build before 1978. Since some of these homes may have not been repainted, the flaking of old lead paint is a source of human exposure to lead poisoning. Sources of human exposure to mercury may be through fish with high exposures of this, and a high intake of fish.

17. Hydroxide ions are found in many bases.

18. Hydrogen atoms are found in most acids.

19. A. Basic
      B. Basic
      C. Acidic
      D. Neutral

20. A. Soft drinks
      B. Black coffee
      C. Milk of magnesia

21. Two times more acidic.

22. Inappropriate pH levels on aquatic organisms cause alkaline solutions are able to dissolve organic materials, including skin and scales. Also, fish-egg development is impaired. This harms the fish to produce.

23. Nonpolar molecules do not dissolve well in polar solvents. On the other hand, polar substances dissolve in polar solvents, while nonpolar substances dissolve in nonpolar solvents. This is known as the "like dissolves like".

24. I would select a lamp oil to dissolve a nonpolar molecular substance because nonpolar molecules are known to not dissolve well in ethanol or water.

25. Table salt (NaCl) will dissolve in water but not in cooking oil because NaCl is a polar substance, therefore it cannot dissolve in oil.

26. The phrase "like dissolves like" means that polar substances dissolve in polar solvents, while nonpolar substances dissolve in nonpolar solvents. Basically, polar with polar, nonpolar with nonpolar.

27. You cannot satisfactorily clean greasy dishes with just plain water because water is polar, and oil (grease) is nonpolar, therefore they do not mix and cannot cancel each other out in a way.

33. Milk of magnesia and oven cleaner contain bases may be found in these cleaners. Using these cleaners is more effective than washing with water because these cleaners are more efficient and get rid of more of the grease with substances that mix with oil better than water.

35. Due to flourine having a higher electron density than hydrogen, I think that hydrogen would have a partial positive charge.