Chem 110 Name__________________

EXAM #1 Topics 1-4 (Check schedule for appropriate text pages, mostly chapters 1, 2, 3, 4) (100 points)

Multiple Choice: 2 points each

CHAP 1

_____1. Which of the following is a physical change?

a) electrolysis of water

b) digestion of food

c) condensation of steam

d) dissolving limestone in rain

_____2. Which of the following is a chemical property?

a) iron reacts with water and air to form rust

b) salt dissolves in water

c) sugar is a solid at room temperature

d) evaporation of water

_____3. Which one is an example of a mixture?

a) distilled water

b) table sugar

c) air

d) baking soda

_____4. An example of a homogeneous mixture would be:

a) Cool-Aid that contains a small amount of sugar

b) vegetable soup

c) oil and vinegar salad dressing

d) freshly opened can of Pepsi

 

_____5. The label on a can of sparkling mineral water lists the following ingredients: carbonated water and natural lime flavor. Which one of the following best classifies the beverage?

a) mixture

b) element

c) compound

d) pure substance

CHAP 3

_____6. Although all parts (postulates) of Dalton's atomic theory are important, which one of the postulates is crucial to explain the observation summarized by the Law of Definite Proportions?

a) Matter is composed of atoms

b) Atoms of the same element have the same properties

c) Atoms combine with other atoms in fixed, whole number ratios to form compounds

d) Atoms are very small

_____7. The law of conservation of mass proves that:

a) atoms are neither created nor destroyed in a chemical reaction

b) all atoms have the same weight

c) all atoms have different weights

d) atoms change weight during a chemical reaction

 

_____8. The application of electricity to chemical systems provided much of the experimental evidence for the existence of subatomic particles. With respect to the use of electricity in probing matter, which one of the following scientists WOULD NOT be grouped with the others?

a) Humphry Davy

b) J.J. Thomson

c) Eugen Goldstein

d) Ernest Rutherford

_____9. Millikan's experimental work allowed the determination of the charge of the electron. When combined with Thomson's determination of the ______?___ of the electron, the mass of the electron could be calculated.

a) speed of the electron

b) mass to charge ratio

c) masso f the electron

d) charge on X-Rays

_____10. A stream of electrons will behave in what way in an electric field?

a) be unchanged

b) be deflected toward the positive electrode because the electron has a positive charge

c) be deflected toward the positive electrode because the electron has a negative charge

d) be deflected toward the negative electrode because the electron has a negative charge

_____11. Based upon the experiments of his co-workers, Rutherford proposed the following: Which is the false statement?

a) atoms are mostly empty space

b) most of the mass of atoms is located in a dense, small volume nucleus

c) the nucleus is positively charged

d) the alpha particles were deflected by the electrons cloud.

_____12. With the discovery of isotopes, which postulates of Dalton's original atomic theory must be modified?

a) Matter is made up of atoms

b) Atoms combine with other atoms in whole number ratios to form compounds

c) Atoms of the same element are the same

d) In chemical reactions, the arrangement of atoms is changed

_____13. Mendeleev organized the elements:

a) by increasing atomic number and similar properties

b) by increasing atomic mass and similar properties

c) by increasing atomic mass only

d) by number of outer energy electrons

CHAP 4

_____14. The lines in an atomic line emission spectrum, explained by Bohr were due to:

a) nuclear transitions in atoms

b) movement of electrons from lower energy states to higher energy states in atoms causing the emission of light

c) movement of electrons from higher energy states to lower energy states in atoms causing the emission of light

d) electrons absorbing light

_____15. Sodium ion, Na+1, has the same number of electrons as a:

a) sodium atom

b) neon atom

c) chloride atom

d) argon atom

_____16. When calcium reacts with chlorine, calcium plus 2 ions, and chloride ions are formed. In this reaction, calcium atoms:

a) lose 2 electrons

b) lose 1 electron

c) gain electrons

d) gain 2 protons

_____17. How many dots will appear in the electron dot symbol for arsenic atom?

a) zero

b) five

c) eight

d) three

_____18. When nitrogen combines with hydrogen, the reaction involves a:

a) transfer of three electrons from N to H

b) transfer of three electrons from H to N

c) sharing of six electrons between N and H

d) conversion of protons into electrons

CHAP 2

_____19. The source of liquid water on the surface of the ancient developing earth was:

 

a) chemical reactions that occurred on the surface.

b) hydrogen and oxygen gases from outer space reacting on the earth's surface

c) hydrogen and oxygen were released from the interior of the earth by volcanic activity as water vapor

d) it came directly from outer space

 

_____20. Which of the following methods were most responsible for providing most of the oxygen in the early atmosphere?

a) photosynthesis of plants

b) photosynthesis of blue-green algae

c) volcanic eruptions

d) combustion reactions

 

_____ 21. The most important usable sources of iron and aluminum ores are in the chemical form of oxides.

a) True

b) False

c) Can not tell

 

22.(4) Classify each of the following as chemical or physical changes.

a) a candle burns in air to produce CO2 and H2O.

b) Candle wax melts and liquefies.

 

 

23.(3) Indicate how many neutrons, electrons and protons are in the following atom.

 

Al atom

24. (6) Use the contributions of all three, Rutherford, Bohr, and the Wave-Mechanical Models, to thoroughly explain your conception of the structure for an atom of sulfur. Also give the proper number and placement of the three particles in an sulfur atom.

 

 

 

 

 

25.(8) Using the carbon cycle, p. 44-46, write chemical reactions (use element symbols or formulas and/or names) which represent the following processes. (It is not necessary to balance equations and in some cases an element or molecule may be missing as you read the text or look at the diagrams. Try to translate words into symbols as much as possible. Do not worry about trying to put in subscripts - numbers which just follow the symbols are OK as in H2O)

a) animal respiration:

 

b) plant photosynthesis:

 

c) decomposer respiration:

d) burning fossil fuels

 

26. (8) Write chemical reactions (use symbols or formulas and/or names) to represent the following processes in the nitrogen cycle, p. 46-47 AND p. 50. (It is not necessary to balance equations and in some cases an element or molecule may be missing as you read the text or look at the diagrams. Try to translate words into symbols as much as possible.)

 

a) nitrogen fixation

 

b) lightning in a thunderstorm to ultimately make nitric acid (several steps)

 

c) nitrification

 

d) denitrification

 

 

 

27.(4) a) List any two of the common structural types of silicates and compare and contrast the chemical structures.

 

 

(3) b) Explain why asbestos was used, why is it dangerous.

 

 

28. (10) Define the following terms and give an example of each. (2 points each)

a. Ionic bonds

 

b. Polar covalent bonds

 

c. Non-polar covalent bonds

 

d. Hydrogen bonds p. 110

 

e. "Likes dissolve likes" p. 178

 

 

29. For this question use: N.Y. Times "Milestone Report on Mercury Emissions". See the text of the article below the questions.

a. (1) What is the source of mercury in this report that needs to be controlled?

b. (3) How is the mercury turned into a more hazardous or toxic form of mercury? What is the name of this chemical? What is the health effect?

c. (6) Give specific details of the chain of events which ultimately leads to children being exposed to this form of mercury? Start with mercury in coal. Use the info on p. 299-301 of the textbook to explain what is meant by accumulation up the food chain. * Use this hint somewhere in your discussion: Fish contain oils, which contain carbon hydrogen bonds, which are non polar, therefore the toxic form of mercury called _______ must be _________ (polar or non polar?)* because "likes dissolves likes".... continue with why it accumulates...

d. (2) What specific experiments are to be conducted to figure out how to control the mercury?

 

Full Text: "Milestone Report on Mercury Emissions"

Copyright New York Times Company July 12, 2000 by Andrew C. Revkin

 

A prestigious panel of scientists declared yesterday that levels of the most hazardous form of mercury in the environment posed an unacceptable health risk to children born of women who eat fish during pregnancy, and should be reduced.

That finding by the 10 experts, convened by the National Academy of Sciences, means that after long delay, the way is now cleared for the Environmental Protection Agency to write new regulations forcing electric power plants, the last large source of unregulated emissions of mercury, to cut them.

The panel's conclusion essentially ends a rancorous debate waged between industry and environmental officials for more than a decade. At issue was how to deal with methyl mercury, a toxic metal that occasionally taints popular seafood like tuna and by now has also prompted 41 states to issue warnings against eating fish caught in many rivers and lakes.

In unambiguous terms, the panel said yesterday that warnings did not suffice. ''The long-term goal,'' its report said, ''needs to be a reduction in the concentrations.''

Coal-burning power plants release more than 40 tons of mercury a year, about a third of the total entering the environment. The environmental agency was poised two years ago to write new mercury rules for plants, but met heavy resistance from members of Congress, who in turn were encountering intense lobbying from the electric power industry. The industry pushed hard for an independent study on the risks of methyl mercury, created in nature by the interaction between mercury and bacteria, and Congress responded by directing the E.P.A. to commission it. The work was undertaken by the 10 scientists, brought together by the academy's National Research Council.

Representatives of the power industry yesterday accepted the panel's conclusions, thereby effectively ending their opposition to the E.P.A.'s plans and shifting the debate over mercury regulation from if to how.

''We wanted this issue about mercury to be settled based on the best science available, and that's essentially what the academy has done,'' said Paul Bailey, vice president for environmental affairs at the Edison Electric Institute, a trade group representing companies that generate three-fourths of the country's electricity.

''We expect the E.P.A. to decide that they are going to regulate mercury from us,'' he said. ''What we're focused on is working with them to fashion a program that makes sense.''

Mr. Bailey said the industry would favor a system of pollution credits much like that which now governs industrial emissions of sulfur dioxide. Environmental groups would oppose that approach.

The panel of scientists estimated that 60,000 children are born each year who were exposed during pregnancy to methyl mercury levels that could cause neurological and learning problems. Most of the exposure comes from fish in their mothers' diet. Through rain and runoff, methyl mercury tends to concentrate in bodies of water, where it accumulates in fish as it passes up the food chain.

E.P.A. officials said they felt vindicated by the report and intended to press ahead with a decision by Dec. 15 on limiting mercury emitted by power plants. That date was set in settlement of a lawsuit brought by some private environmental groups to force the agency to consider mercury cuts under provisions of the Clean Air Act.

The report ''underscores and reinforces the science that will go into that policy decision and others that will follow with regard to controlling mercury,'' said David Cohen, a spokesman for the environmental agency.

Environmental groups said the end of the scientific debate over power plants was long overdue, noting that they were the last large uncontrolled source of mercury emissions. David Hawkins, director of air and energy programs for the Natural Resources Defense Council, pointed out that as a result of government regulation already in effect, owners of incinerators, another big source, were adding filters and other equipment to capture the metal before it leaves smokestacks.

The debate now shifts to how best to cut the flow of mercury from coal to power-plant smoke and on into the environment. Last year the E.P.A.

initiated the first significant study of the problem, requiring not only that all power plants measure the amount of mercury in coal through 1999 but also

that several dozen measure the amounts emitted from smokestacks before and after the installation of filters.

The report issued yesterday, after the scientists' 18-month review of the E.P.A.'s risk calculation for mercury, concluded that the most important hazard

by far lay in the threat to developing fetuses.

It emphasized that the risk to most people was very small, and that the primary goal was to cut the exposure in young women who frequently eat fish

in which the highest levels of mercury tend to accumulate -- generally predatory sea fish like tuna and swordfish but also some freshwater fish in places

with high mercury levels.

Federal officials said the report could also be an influence in whether the Food and Drug Administration tightens its standards for fish. The food

agency now uses a much less aggressive risk calculation than the E.P.A. calculation endorsed by the scientists yesterday. F.D.A. officials said they

had not yet had time to review the mercury report.