9) Calculate the masses of water and sugar in a 55.0-g sugar solution that is labeled 20.0% sugar by mass.
.20 x 55 = 11
11g sugar.
55-11 = 44
44g water.
11g sugar, 44g water.
10) The EPA maximum standard for lead in drinking water is 0.015 mg/L. Express this value as parts per million (ppm).
15,000ppm.
11) What makes a water molecule polar?
Since water has an uneven distrobution of electrical charge, where the end of the oxygen atom is negatively charged and the ends of the hydrogen atoms are positively charged, a water molecule is polar.
12) Draw a model that shows how molecules in liquid water generally arange themselves relative to one another.
See drawing.
13) Which region of a polar water molecule will be attracted to a
a. K+ ion?
b. Br- ion?
a. The negatively charged end, the oxygen end.
b. The positively charged end, the hydrogen end.
14) Why are heavy metals called heavy?
Heavy metals are called heavy because thheir atoms have greater masses than those od essential metallic elements, and therefore, are harmful to humans and other organisms.
15) List three symptoms of heavy metal poisoning.
Numbness, staggered walk, tunnel vision, and brain damage are (four) symptoms of heavy metal poisoning. Heavy metal poisoning can lead to death; it causes damage the nervous system, brain, kidneys, and liver.
16) List two possible sources of human exposure to
a. lead
b. mercury.
a.
1) Soil surrounding heavily traveled roads, for it may have absorbed automobile exhaust from the gas from cars that contained tetraethyl lead before the 1970s.
2) Flaking leaded paint in houses built before 1978/.
b.
1) Thermometers and florescent light bulbs.
2) Fish exposed to mercury in the water.
17) What ion is found in many bases?
Hydroxide (OH-) is found in many bases.
18) What element is found in most acids?
Hydrogen (H) is found in most acids.
19) Classify each sample as acidic, basic, or chemically neutral:
a. seawater (pH = 8.6)
b. drain cleaner (pH = 13.0)
c. vinegar (pH = 2.7)
d. pure water (pH = 7.0)
a. basic.
b. basic.
c. acidic.
d. chemically neutral.
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