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1 | |
A 4.065 g sample of iron (III) oxide was decomposed into iron and oxygen, yielding 3.557 g of iron. How many grams of oxygen were obtained? |
| | A) | 1.001 g |
| | B) | 0.508 g |
| | C) | 1.016 g |
| | D) | 0.625 g |
| | E) | 0.552 g |
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2 | |
What is the molecular mass of CH3OCH3? |
| | A) | 59.45 amu |
| | B) | 45.35 amu |
| | C) | 57.02 amu |
| | D) | 46.06 amu |
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3 | |
Calculate the formula mass of Ba(NO3)2. |
| | A) | 261.33 amu |
| | B) | 170.84 amu |
| | C) | 234.42 amu |
| | D) | 147.82 amu |
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4 | |
Calculate the number of molecules in 4.53 moles of carbon dioxide. |
| | A) | 2.73 x 10 24 |
| | B) | 6.022 x 10 23 |
| | C) | 4.01 x 10 25 |
| | D) | 1.01 x 10 22 |
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5 | |
By drawing the correct Lewis structure of CO2, determine which description of its molecular geometry and predicted bond angle are correct. |
| | A) | tetrahedral, 109.5o |
| | B) | trigonal planar, 120o |
| | C) | linear, 180o |
| | D) | bent, 90o |
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6 | |
The carbon cycle describes the exchange of carbon between the atmosphere, land, and water. Which processes add carbon, in the form of carbon dioxide, to the atmosphere?
I. deforestation by cutting and burning trees
II. deposition of calcium carbonate in the oceans
III. combustion of fossil fuels
IV. respiration of humans and animals |
| | A) | I, II, III only |
| | B) | I, III only |
| | C) | I, III, IV only |
| | D) | II, III, IV only |
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7 | |
How does the term "greenhouse effect" differ from the term "global warming"? |
| | A) | The terms do not differ at all but refer to the same thing. |
| | B) | The term "greenhouse effect" refers only to processes in a limited region of the Earth's surface. "Global warming" refers to processes that are global in nature. |
| | C) | The term "global warming" refers to the return of 84% of heat energy to earth. "Greenhouse effect" refers to an increase in that effect caused by increasing concentrations of greenhouse gases. |
| | D) | The term "greenhouse effect" refers to the return of 84% of heat energy to earth. "Global warming" refers to the increase in that effect caused by increasing concentrations of greenhouse gases. |
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8 | |
Possible consequences of continued global warming include |
| | A) | lowered sea levels, leaving present coastal areas far inland. |
| | B) | altered climates and changes in agricultural productivity. |
| | C) | increased deforestation in areas such as the American Midwest and South American rain forests. |
| | D) | further destruction of the ozone layer, leading to increased skin cancer. |
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9 | |
Caffeine has the formula C8H10N4O2. How many molecules are in 10.0 g of pure caffeine? (The molar mass of C8H10N4O2 is 194 g/mol.) |
| | A) | 8.6 x 10-26 |
| | B) | 3.1 x 1022 |
| | C) | 6.0 x 1024 |
| | D) | 1.2 x 1027 |
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10 | |
Consider the following information about two greenhouse gases:
The gas N2O has a greenhouse factor of 160 and an abundance in the troposphere of 3.0 x 10-5%. CCl2F2 has a greenhouse factor of 25000 and an abundance in the troposphere of 4.8 x 10-8%.
Which statement is correct? |
| | A) | CCl2F2 is a more effective greenhouse gas than is N2O, and there is less of it in the troposphere. |
| | B) | CCl2F2 is a less effective greenhouse gas than is N2O, and there is less of it in the troposphere. |
| | C) | CCl2F2 is a more effective greenhouse gas than is N2O, and there is more of it in the troposphere. |
| | D) | CCl2F2 is a less effective greenhouse gas than is N2O, and there is more of it in the troposphere. |
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11 | |
Given that direct measurements of the earth's atmospheric composition over the last several thousands of years are not available, how can scientists know the fluctuations in the concentration of carbon dioxide in the past? |
| | A) | Ice cores drilled at the Vostok Station in Antarctica have been analyzed for the ratio of carbon-13 to carbon-12. |
| | B) | Computer modeling of the composition of primitive atmospheres has produced the CO2 evidence. |
| | C) | Current CO2 measurements are combined with information on the alignment of magnetic fields in dinosaur bones. |
| | D) | Samples from the ocean floor have been analyzed for CO2 trapped in air bubbles in the sedimentary layers. |
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12 | |
Which factors should be considered when deciding which greenhouse gases should be targeted for control?
I. greenhouse factor
II. relative abundance
III. atmospheric lifetime |
| | A) | I and II only |
| | B) | I, II, and III |
| | C) | I and III only |
| | D) | II and III only |
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13 | |
How many grams of CO2 are needed to be sure of having exactly 3.0 x 102 mol of CO2? |
| | A) | 3.0 x 102 g |
| | B) | 6.6 x 103 g |
| | C) | 1.3 x 104 g |
| | D) | 1.8 x 1026 g |
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14 | |
A certain brand of skin moisturizer advertises that it contains SPF 15 sunscreen that protects from UVA and UVB rays. Why isn't UVC mentioned in its product claims? |
| | A) | UVC radiation is not absorbed by ozone, so it has no connection to the story of increased exposure to UV rays or ozone depletion. |
| | B) | UVC radiation is not as dangerous as is UVB radiation, so whether or not we are shielded from it does not matter. |
| | C) | UVC radiation is extremely dangerous, but it is completely absorbed in the upper atmosphere by oxygen, O2, as well as by ozone, O3. |
| | D) | There is no need. UVC radiation is a natural part of the electromagnetic spectrum, so it only has the same potential for harm as visible light. |
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15 | |
HFC's are being developed to replace CFC's. Which of these compounds is an HFC? |
| | A) | CCl2F2 |
| | B) | CH3CFCl2 |
| | C) | CCl3CFCl2 |
| | D) | CF3CH2F |
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