Homework 7/16/13

13. 

a. 6 moles

b. 5 moles

c. 5 moles 

14. 

a. 2 moles

b. 621 grams

c. 28 grams

d. mass of 446 grams 

15. Even though the percent of the oxygen atoms is 67%, since oxygen's molar mass is 32 and carbon's molar mass is 12 in this molecule, The percent oxygen by mass 32g/44g x 100%, or 73%. 

16. 

a. total molar mass is 248, metal molar mass is 216.

216/248= 87% 

b. total molar mass is 102, metal molar mass is 54.

54/102= 53% 

c. total molar mass 100, metal molar mass is 40

40/100= 40% 

17.

a. total molar mass is 303, lead molar mass is 207

207/303=68%

b. 5/50= 10%

c. 68*.10=6.8%

18.

a. Reusing is the use of the same item multiple times for the same, or different tasks the item is applicable to. Recycling is when an item is reprocessed into a a different item made of parts, or all of the same substances.

b.

Reusing: water bottles, plastic containers, paper.

Recycling: Cans, paper, glass, plastic.

19.

a. water, air, soil, water, plants

b  gold, silver, copper, natural gas

20.

a. reusing.

b. recycling.

c. reusing.

21. Both glass from a light bulb and paper from a newspaper can be recycled. In since paper that is not recycled leaves a high proportion of combustibles as waste, the newspaper can be sent to a waste-to-energy plant to produce energy that can be used to power the light bulb.