Sunday, June 26, 2011

Homework C.8-C.9

9. Calculate the masses of water and sugar in a 55.0 g sugar solution that is labeled 20.o% sugar by mass.
11grams

10. The EPA maximum standard for lead in drinking water is 0.015 mg/L. Express this value as parts per million (ppm).
15ppm

11. What makes water molecule polar?
The positive and negative charge at the opposite ends.

13. Which region of a polar water molecule will be attracted to a 
a K+ ion
K- Ion
b. BR-
Br+

14.Why are heavy metals called heavy?
Because their atoms have greater masses than those of essential metallic elements

15. List three symptoms of heavy metal poisoning
-Damage to nervous system
-Damage to the brain
-Damage to the kidney.

16. List two possible sources of human exposure to 
a. Lead
When the water goes through lead pipes, it could pick up some of its chemical
b. Mercury
The old thermometer 

17. What ion is found in many bases
Hydroxide ions, Sodium hydroxide, barium hydroxide

18. What element is found in most acids?
Hydrogen 

19. Classify each sample as acidic, basic or chemically neutral:
A. Seawater (pH = 8.6)
Basic
B. Drain cleaner (pH= 13.0)
Basic
C. Vinegar (pH - 2.7) 
Acidic
D. Pure water (pH - 7.0)
Chemically neutral

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