ISCS (p.82-83) #9-19

6/30/13

9.
-55 x .20 = 11g (mass of sugar)
-55 - 11 = 44g (mass of water)

10.
-0.015 x 1,000,000 = 15,000 ppm

11. What makes water molecules polar is the end that contains the oxygen is negative and the end that contains the hydrogen is positive; therefore, making an attraction that forms H2O.

12. How molecules in liquid water arrange themselves relative to one another:

13.
   a. oxygen molecule: O-
   b. hydrogen molecule: H+

14. Heavy metals are called "heavy" because their atoms have greater masses than those of essential metallic elements, and are therefore harmful to humans and other organisms.

15. Three symptoms of heavy- metaled poisoning include damages to the nervous system, brain, kidney, and liver.

16.
   a. Two possible human exposures to lead include  paint/pottery and the transportation of water through lead pipes.
   b. Two possible human exposures to mercury include medical and weather thermometers and fluorescent light bulbs.

17. The ion that can be found in many bases is the hydroxide ion (OH-).

18. The element hydrogen (H) is found in most acids.

19.
   a. seawater: basic
   b. drain cleaner: basic
   c. vinegar: acidic
   d. pure water: neutral


ISCS (p.83) #20-27, 33, 35
20.
   a. soft drinks
   b. black coffee
   c. milk of magnesia

21. A solution at pH 2.0 is 20 times more acidic than a solution at pH 4.0.

22. Three negative effects of inappropriate pH levels on aquatic organisms are:
- Too low pH (acidic)
    - fish egg development is impaired causing reproduction to be more difficult
    - increased concentrations of metal ions in natural waters by the leakage of metal ions from surrounding soil
- Too high pH (basic)
   - dissolves organic material like skin on humans or scales on fish

23. Polar molecules have different charges at each end. One end is positive and one end is negative. Nonpolar molecules are balanced at both ends, they don't have these different charges. Polar molecules dissolve in polar solvents and nonpolar molecules dissolve in nonpolar solvents.

24. I would pick lamp oil to dissolve a nonpolar molecular substance because oil is a non polar solvent, and since nonpolar molecules dissolve in nonpolar solvents, the nonpolar molecular substance would; therefore, dissolve in lamp oil better than in water and ethanol sine these two are polar molecules.

25. Table salt (NaCl) dissolves in water but not cooking oil because water is polar and can, then, attach to the positive and negative charges of NaCl, causing the salt to pulled apart and dissolve in water. And since cooking oil is nonpolar, it doesn't have this same effect.

26. The term "like dissolves like" refers to pattern of solubility behavior, which is polar substances dissolve in polar solvents, and nonpolar substances dissolve in nonpolar solvents. Therefore, a polar substances will not dissolve in a nonpolar solvent, and likewise if a nonpolar substance tries dissolving in a polar solvent.

27. You cannot satisfactorily clean greasy dishes with just plain water because greasy dishes contain oil which is nonpolar, and water is polar. And because "like dissolves like" a nonpolar substance cannot be dissolved in a polar solvent. Which is why you need to add soap to the water to help dissolve the substances.

33.
   a. The kind of materials that are likely to be found in these waterless hand cleaners would be nonpolar substances.
   b. Using these cleaners would be more effective than washing with water because the greese, which is nonpolar, cant be dissolved by water, which is polar. So these cleaners are capable of cleaning the grease because they are nonpolar.

35. In HF, I would expect hydrogen (H) to have a particle positive charge. This is because fluorine (F) has the greatest electronegativity of any element, meaning it has a higher concentration of electrons, which are negative. Which means hydrogen would have to be positive if the fluorine (F) is a particle negative charge.