Chemistry 100 version-A

Exam I / September 26

Part II -- multiple choice (60 points)

• There were three versions of the exam. Same questions but the order varied.
• correct answer in bold type
• comments (not on the exam) are in italics

1. Air is an example of

• a. a chemical element
• b. a chemical compound
• c. a mixture
• d. an isotope
• e. an allotrope

• a. plays no significant chemical role in your body
• b. is converted by your body to ammonia (NH₃)
• c. is used by your body to create proteins
• d. is converted in your body to Nitrogen Oxide
• e. is toxic at concentrations in excess of 300 parts per million

• a. If you hit gold with a hammer (mallet) it is strong and changes little
• b. If you hit gold with a hammer (mallet) it distorts and changes shape
• c. If you hit gold with a hammer (mallet) it tends to shatter
• d. Gold is favored by jewelers and you find jewelers in a mall.
• e. Pure Gold has a faint but unpleasant smell (is malodorous).

• a. Plumbing symbol is Pb
• b. Ledger
• c. Logic
• d. Ferris (as in a Ferris Wheel)
• e. Pencil

• a. contains protons, neutrons and electrons
• b. contains protons and electrons
• c. contains protons and neutrons
• d. is electrically neutral
• e. contains less than half of the mass of the atom

• a. Over 95% of dry air is composed of a single element
• a. Two elements constitute about 99% of dry air (nitrogen and oxygen)
• b. Air is about 80% oxygen
• c. Air pollutants are now average about 1-3% of the content of air (No, usually in ppm)
• d. Air quality in large industrial cities in the US is getting worse and is now at the worst level in the past century. (We may talk louder, but air is actually much cleaner.)

• a. an area of the upper atmosphere with decreased Ozone
• b. an area of the upper atmosphere with no Ozone
• c. an area in the ocean where Ozone is normally trapped
• d. an alternative to chlorofluorocarbons (CFC's) in new refrigeration systems
• e. a column of moving air that brings Ozone down to the lower parts of the atmosphere

• a. Is the major factor in most "global warming" scenarios
• b. Is the major carbon component formed when gasoline or coal burns
• c. Is more toxic than Carbon Dioxide
• d. Has the Formula C₂MnO₂
• e. Can attach to hemoglobin and supply oxygen to body tissues (can attach, but keeps hemoglobin from transporting oxygen)

• a. is obtained as a secondary product during the purification of Aluminum ore
  • Ga is in the Al family (below it on periodic table) and likely t have similar chemistry and therefore present in same places. It also fits in the metals area and is not likely to be a gas. Likewise, the middle of the table does not contain extremely reactive elements.
  • The answer was not a fact you should have known-- but something you had information to deduce.
• b. is a diatomic gas (Ga₂) found in natural gas deposits
• c. reacts violently ( in a manner similar to sodium) when it is placed in water

10. When Potassium reacts with Bromine, the product is called

• a. potassium bromine
• b. potassium bromide
• c. bromopotassium
• d. bromine potaside
• e. George

• a. 0.001
• b. 1
• c. 100
• d. 1000
• e. 454

• a. liquid nitrogen would remain a liquid
• b. water would begin to freeze
  • don't confuse with 32o F (water's freezing point)
  • Celsius is 0o = freezing water, 100o= boiling water
  • 32oC must be in between and only c is viable
  • (One of the TA's complained that 32C wasn't hot enough for his idea of hot coffee)
• c. coffee would be hot, yet drinkable (assuming you like coffee)
• d. water would begin to boil
• e. metals like Tin would begin to melt

• a. 20 centimeters
• b. 0.002 kilometers (2 meters, a bit over 2 yards or six feet)
• c. 65 kilograms
• d. 6 liters
• e. 75% relative humidity

• a. 0.0032
• b. 0.032
• c. 32
• d. 3200
• e. 103.2

_?_FeO + _?_Al ----> _?_Al₂O₃ + _?_Fe

The four numbers needed to balance the equation are (in order)

• a. 1, 1, 2, 1
• b. 2, 2, 1, 2
• c. 3, 2, 1, 3
• d. 3 ,2, 2, 3
• e. none of the above

16. The element S (atomic number 16-- see periodic table on page 1)

• a. is likely to form a +2 Ion (No, a -2 Ion)
• b. is likely to form a -1 Ion
• c. is likely to be very inert
• d. probably forms a compound H₂S with Hydrogen
  • lies below oxygen on periodic table; should resemble it and we know H₂O
• e. probably has chemical properties most similar to those of neighboring elements P (atomic number 15) and Cl (atomic number 17)

• a. has a mass of (1 / 44.0) grams
• b. has a mass of 44 grams
• c. has a mass of 44 kilograms
• d. has a mass of 6.023 x 10^-23 grams
• e. has the same mass as one mole of any other chemical compound

• a. Aluminum
• b. Oxygen
• c. Hydrocarbon
• d. Fluorine
• e. Sodium

• a. The sodium ion is very unreactive (boring)
• b. Gold metal is useful because it is chemically unreactive (boring)
• c. Iodine (I₂) is useful as a disinfectant because it is reactive
• d. Bronze is an ancient term for what we now call copper
  • bronze is a copper alloy
• e. Gold and Copper were used long before the Iron Age.

20. One atom of the isotope ²³₁₁Na

• a. contains 11 neutrons
• b. contains 23 electrons
• c. contains 11 electrons
  • nucleus has 11 protons and 12 neutrons (not on the list)
  • the neutral atom has 11 electrons
• d. contains 12 protons
• e. contains 11 sodium nuclei

• a. The mass of reactants = the mass of products (conservation of matter)
• b. The number of reactant molecules = number of product molecules
• c. Volume of reactant = volume of products
• d. The reactants are chemical elements and the products are chemical compounds
• e. Atoms may change into atoms of lower atomic mass but not higher atomic mass

• a. NO
• b. NO₂
• c. N₂O
• d. N₂O₄
• e. N₂O₅

• a. red light
• b. blue light
• c. ultraviolet light
• d. infrared light
• e. microwaves

• a. Burning the fuels produces heat
• b. CO₂ is a species that can prevent the escape of infrared radiation
• c. CO₂ is very efficient at absorbing sunlight
• d. CO₂ from fossil fuels contains little or no ¹⁴C due to their age
• e. The earth lacks a mechanism for the removal of CO₂

• a. the official naming of the elements and their symbols
• b. ozone levels in the upper atmosphere
• c. global warming and greenhouse gases
• d. reduction of sulfur dioxide levels from the combustion of high sulfur coal
• e. the import of automobiles from Japan and Korea

27. The Periodic Table contains about 110 Chemical elements. Which statement best describes these elements

• a. over half of the elements are gases or liquids at room temperature
• b. over half of the elements are classified as metals
• c. the elements in the center block of the table are called Halogens
• d. the first column (I-A) contains the Inert Gases (also called the Noble Gases)
• e. all the elements occur naturally in the earth or atmosphere, although some are present at very low concentrations.

• a. Ozone is toxic and this ozone will eventually reach the air we breathe
• b. Ozone absorbs hazardous light from the sun
  • of course the concern is that this process might become less effective
• c. Ozone absorbs the sunlight needed for photosynthesis
• d. Ozone can produce dangerous levels of CFC's
• e. Ozone reacts with CO₂ and decreases the CO₂ concentration

• a. none
• b. two
• c. four
• d. six
• e. eight

30. Which of the statements about ionic species is NOT true

• a. Ionic compounds always include both positive and negative ions
• b. Ions can contain several atoms within a single ion.
  • true-- Ions like OH- and nitrate, NO₃- ,are common
• c. An Na⁺ ion contains fewer electrons than a sodium atom
• d. Calcium Chloride, CaCl₂, is an ionic compound with one calcium ion and two chloride ions in each calcium chloride molecule
  • ionic compounds do not exist as discrete molecules
• d. Water (H₂O) is not an ionic compound

• Part I will take a little longer to get posted

return to chemistry 100 home page