HW #10

1SCS 3 9-19

9.  Mass of sugar: -55 x .20 = 11g
     Mass of water: -55 - 11 = 44g

10. 15,000 ppm

11. The water molecule is polar because at one end it contains oxygen, which is more electronegative than hydrogen so electrons are partially pulled away from the hydrogen on the other end to the oxygen making one end negative and the other end positive.

12. 

13. a) oxygen  b) hydrogen

14. Heave metals are called "Heavy" because their atoms have a greater mass than metallic elements, which makes them harmful to living organisms.

15. Damages to the nervous system, brain, kidney, and liver.

16. a) Paint and lead pipes.  b) thermometers and fluorescent lights

17. Hydroxide ion (OH-)

18. Hydrogen (H)

19. a) basic  b) basic  c) acidic  d) neutral


1SCS # 20-27, 33, and 35

20. a) soft drinks   b) black coffee   c) milk of magnesia

21) A solution is 20 times more acidic at 2.0 than 4.0 because there is a tenfold difference.

22. Too low of a pH lever, impaired fish egg development, an increase of concentrations of metal ions in natural water from surrounding soil, too high of a pH level, and metals being dissolved in the skin of humans or the scaled of fish.

23) A molecule with regions of partial positive and negative charge resulting from the uneven distribution of electrical charge. A nonpolar molecule is a molecule that has an even distribution of electrical charge with no regions of partial positive and negative charge.

24) Lamp oil because it is nonpolar.

25) NaCl is a polar molecule, so it dissolves in water, which is also a polar substance. Oil is non polar, so it does not dissolve well in water.

26) The phrase “like dissolves like,” explains solubility behavior. Polar substances dissolve is polar solvents and non polar substances dissolve in nonpolar solvents.

27) Water is composed of polar molecules while grease is composed of nonpolar molecules, which means that the water would not be able to dissolve the oil off the pan.

33)  a) Non polar materials   b) These cleaners are nonpolar and could dissolve the grease off their hands. 

35) If fluorine has the highest electronegativity than it also must have the most electrons, so it is negative. Therefore, hydrogen has less electrons and has a positive charge.