Q1) Because of increasing evidence of damage to the ozone layer, chlorofluorocar

Question

Q1)

Because of increasing evidence of damage to the ozone layer, chlorofluorocarbon (CFC) production was banned in 1996. However, there are about 100 million auto air conditioners that still use CFC12 (CF2Cl2).
These air conditioners are recharged from stockpiled supplies of CFC12.

Part A

If each of the 100 million automobiles contains 1.0 kg of CFC12 and leaks 22 % of its CFC12into the atmosphere per year, how much chlorine, in kg, is added to the atmosphere each year due to auto air conditioners? (Assume two significant figures in your calculations.)

Express your answer using two significant figures.

Q2)

A particular coal contains 2.55% sulfur by mass. When the coal is burned, it produces SO2emissions which combine with rainwater to produce sulfuric acid.

Determine how much sulfuric acid (in metric tons) is produced by the combustion of 1.0 metric ton of this coal. (A metric ton is 1000 kg.)

Express your answer using two significant figures.

Q3)

Lead is found in Earth's crust as several different lead ores. Suppose a certain rock is composed of 38.0% PbS (galena), 25.0% PbCO3 (cerussite), and 17.4% PbSO4 (anglesite). The remainder of the rock is composed of substances containing no lead.

Part A

How much of this rock (in kg) must be processed to obtain 5.2 metric tons of lead? (A metric ton is 1000 kg.)

Express your answer using two significant figures.

Q4)

A compound of molar mass 213 contains only carbon, hydrogen, iodine, and oxygen. Analysis shows that a sample of the compound contains 6 times as much carbon as hydrogen, by mass.

Part A

Calculate the molecular formula of the compound.

Express your answer as a chemical formula. Enter the elements in the order: C, H, O, I.

Q5)

A particular brand of beef jerky contains 6.01×102% sodium nitrite by mass and is sold in an 8.00-oz bag.

What mass of sodium does the sodium nitrite contribute to sodium content of the bag of beef jerky?

Express your answer to three significant figures and include the appropriate units.

Explanation / Answer

1) 1 kg of Freon leaks per car and 22% leaks into the atmosphere

atomic weight of chlorine =71

Atomic weight of Freon -12 = 120.9

71 kg of chlorine is added per 120.9 kg of Freon

Total number of automobiles =100 million =100X106

Freon per car = 100X106 cars*1kg/car =1X108 kg

22 kg of freon leaked per 100 kg

Freon leaked = =(22/100)X108 = 22X106kg

Kg chlorine/ kg freon = (71/121.9)

Chlorine leaked = (71/121.9)*22X106 =12.813X106 kg Chlorine

b)

Mass % of S = 32/ (1.0 x 2 + 32 + 4X16) x 100% = 33.06%

Mass of sulfur in the coal = 2.55/100 x 1100 = 28.05 kg

Mass of sulfuric acid formed = 28.05 x 100/33.06 = 84.8 kg = 0.0848 metric tons

c) Atomic weigh of lead =207

atomic weight of PbS =207+32=239

38.0% PbS corresponds to

38%*(209 / 239) = 32.9 % Pb

Atomic weight of PbCO3 =207+12+3*16= 267

25.0% PbCO3 correspondss to 25%*(207.2 / 267) = 19.4 % Pb
Atomic weight of PbSO4 =207+32+4*16=303

17.4% PbSO4 corresponds to

17.44 (207 / 303)= 11.90% Pb

Total lead % = 32.9 + 19.4+11.9 =63.7 %

lead to be processes to provide 5200 kg of lead =5200/ 0.637 =8163 kg of rock

c) Iodine molar mass = 127 /gmole

Since the compound molecular weight is 213, it contains only one iodine'

Balance =213-127=86

Ratio of C: H =6:1

Let the mass of mixture of Carbon and hydrogen be 7

Moles of Hydrogen =1/1 =1

Moles of Carbon= 6/12 = 0.5 total moles =1+0.5=1.5

Ratio of C :H =0.5 : 1 =2:1

That is it gives rise to CH2 , moleculwr weight = 14

Assuming 1 oxygen atom whole atomic weight =16

Balance =(86-16)/14= 5

It contains 5 CH2 units

Hence formula is C5H10OI

d)

.6.01/100 * 8 oz = 0.004808 oinces of sodium

converting to grams:
(0.0048 ounces of sodium) (28.35 grams / oz) = 0.1104 grams of sodium
0.1104 grams of sodium

so your total % Pb =
32.903 % Pb + 19.386 % Pb + 11.888 % Pb = 64.177 % Pb


now we will convert this into the amount of rock that can provide 5,800 kg of Pb
5.8 e3 kg of Pb % 100% rock / 64.177 % Pb = 9037.5 kg of rock

chlorine added per kg of freon = 0.22*(71/121.9)X106 =0.129X106

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