Chem 105 Final – Flashcards
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| The best description of a hypothesis |
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| It can be accepted or rejected but never proven true |
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| Someone who is searching for a better refrigerant is engaged in: |
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| Basic research |
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| Imagine a scientist discovers a new compound with an unusual chemical structure in a plant cell. Based on very preliminary data, the scientist offers a tentative explanation for the purpose of the compound in cells. His explanation would be referred to as a: |
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| Hypothesis |
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| How long does it take to bring the average drug to market? |
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| 12-14 years |
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Lincoln Journal Star injury rate
5600 children fall out of windows; population was 280,000,000
What is the proper way to report this injury rate?
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| 2 childhood window injuries per 100,000 people |
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Cigarette law question
Using only the graph to right, what must have been the most compelling argument for adding the cancer warning? |
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| There is a 25-35 year lag between cigarette sales and the incidence of lung cancer |
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| Which is not a physical property? |
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| Flammability |
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Electric Pickle Experiment:
Which of the following facts or hypotheses is the best explanation for this observation? |
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| The sodium ions in the pickle became excited when they reacted with electrons to produce energy |
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| What is chemsitry? |
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| Anything with mass and volume and its reactions |
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| A pure substance that cannot be broken down into simpler substances by chemical or physical means would be an: |
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| Element |
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| When a newly discovered substance cannot be separated further by any physical process but it can be separated by chemical processes. The new substance must be a: |
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| Compound |
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| Which of the following elements is a liquid at room temperature? |
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| Hg, mercury |
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| The element Cl is a ____ and its name is ____ |
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| Gas, chlorine |
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| Which of the following is a heterogenous mixture? |
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| Mud |
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| Which of the following elements is found in the superstrong magnets used in most cellphone speakers? |
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| Nd, neodymium |
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| Which of the following is an example of physical change? |
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| Water when heated forms steam |
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| An example of a change in physical state would be: |
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| Sublimation of carbon dioxide |
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Which of the following is a correctly balanced equation?
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4Fe + 3O(2) ---> 2Fe(2)O(3)
*numbers in parentheses are subscript |
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| How many atoms are found in the compound Al(2)[SO(4)](3) |
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| 17 |
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| Seven elements normally exist in nature as two atoms bonded together. These elements are known as: |
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| Diatomic molecules |
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| Which set of calculations below would correctly convert 52 ft to centimeters? |
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| (52)(12/1)(2.54/1) |
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| If a tablet contains 201g of a drug, how many milligrams does it contain? |
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| 2.01 x 10^5 |
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| Most atoms and molecules fall into which size range? |
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| Nanometers to micrometers |
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| If a sample of pure matter contains only one kind of atom, it is a(n) _____ and _______ be broken down to simpler substances |
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| Element; cannot |
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Jaconine is an alkaloid isolated from the plant Senecio jacobea. Jaconine's structure was determined in 1959 and it has the molecular formula C(18)H(26)ClNO(6). How many different types of atoms are in one molecule of jaconine? ; *numbers in parentheses are subscript |
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| 5 |
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| The equation 2C(2)H(6)(g) + 7O(2)(g) ---> 4CO(2)(g) + 6H(2)O(g), does not tell us that: |
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| The reaction will produce heat |
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| Convert 0.085954 to scientific notation with 4 significant figures |
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| 8.595 x 10^-2 |
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When the following equation is correctly balanced, what is the coefficient for copper?
__ CuSO(4) + __ Fe ---> __ Cu + __ Fe(2)[SO(4)](3)
*numbers in parentheses are subscript |
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| 3 |
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| The ground state of an atom is one in which |
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| All electrons are in their lowest energy level |
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| Electrons that occupy the energy level just beyond the core electrons are: |
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| Valence electrons |
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| Which statement below most accurately describes the emission line spectra of excited atoms? |
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| Bright lines of color at specific wavelengths separated by dark bands with no color |
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| A form of electromagnetic radiation with more energy than x-rays would be: |
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| Gamma rays |
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| Which color of visible light has the least amount of energy per photon? |
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| Orange |
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| Which part of Dalton's atomic theory has had to be revised due to new discoveries? |
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| All atoms of an element have the same mass |
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Which element below will have the smallest atomic radius?
Tin Sulfur Phosphorous Oxygen |
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| Oxygen |
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| The isotope of lead, Pb-206 contains how many neutrons? |
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| 124 |
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| Colors of light seen in a fireworks display are due to: |
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| Electrons emitting energy in the visible spectrum |
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| What is the correct electron configuration for chlorine? |
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| 1s22s22p63s23p5 |
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Which equation would be best to calculate the frequency of light emitted by a yellow traffic signal if the energy of the radiation was known? |
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| E=hv |
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| Which of the following is not true about particulates? |
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| Gravity and precipitation remove so many particulates from the hair that they are the major cause of river silting |
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| What is the symbol for a neutral atom with 12 protons, 12 electrons, and 12 neutrons |
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| Mg |
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| Radiation penetrates from most to least according to the order: |
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| gamma>beta>alpha |
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| Atoms become destabilized when their nuclei contain too many or too few |
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| Neutrons |
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| Which element is found in Group 6B - in Period 4 |
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| Chromium, Cr |
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| What is the largest source of background radiation contained within your body? |
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| Potassium, K |
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| What is the number of valence electrons in Magnesium (Mg) |
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| 2 |
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Which element would most likely have the Lewis Dot Symbol
* * X * * |
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| Carbon, C |
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| Which part of Bohr's model of the atom provides the best explanation for the emission of visible light? |
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| When electrons fall from high to lower energy levels, energy is emitted in the form of light |
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| A signifying component of photochemical smog is: |
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| Nitrogen monoxide |
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| Which represents the electron configuration for an atom of unreactive monatomic gas? |
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| 1s22s22p2 |
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| Catalytic converters reduce air pollution reacting with: |
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(all of the above)
NOx SO2 CO |
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| Commercial liquid nitrogen is produced from the air by |
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| Refrigeration of air and fractional warming or fractional distillation |
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| If the concentration of the element named for the planet Krypton, KR, is 304 ppb, what is its percentage |
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| 0.0000304 |
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| Which of the following is not true about ozone? |
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| It is removed from automobile exhaust by the catalytic converter |
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| Which of Nebraska's Energy Sources contributes the most sulfur dioxide to the atmosphere? |
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| Coal |
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| The "valence shell electron pair repulsion" theory is useful in determining: |
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| The shape of a compound from its Lewis Dot structure |
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| The compounds CH4 and NH3 each have four electron groups around the central atom, but they have different molecular shapes. Why do the shapes differ? |
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| Nitrogen has a lone pair and carbon doesn't |
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| The subscripts in the formula for a compound, such as Na3, represent |
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| The numerical ratio of atoms or ions in the compound |
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| Which bond has the most covalent character? |
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| P-Cl |
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| Which statement is NOT true about covalent compounds? |
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| Covalent compounds tend to have high boiling points |
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| Which equation represents the process of methanogenesis? |
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| CO2 + 4H2 ---> CH4 + 2H2O |
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| Which is not an anthropogenic source of methane gas? |
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| Swamps/wetlands |
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| Factors affecting the rate of a reaction include: |
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Temperature Concentration Presence of a catalyst
(all the above) |
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| What is the molar mass of Vitamin C (C6H8O6)? |
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| 176 g/mol |
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| Use VSEPR to predict the atomic shape of the nitrogen in nitric acid |
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| Trigonal planar |
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| A type of bond in which two atoms are sharing electrons equally is known as a |
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| Nonpolar covalent bond |
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| In a molecule of carbon dioxide, CO2, the type of bonding between the carbon and each oxygen is: |
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| Double covalent |
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| One mole of oxygen atoms represents |
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| 6.02 x 1023 atoms |
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When the following equation is correctly balanced, what is the coefficient for copper?
__ CuSO4 + __ Fe --> __ Cu + __ Fe2(SO4)3 |
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| 3 |
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| When the Lewis electron dot structure for AsI3 is correctly written, what is the shape of the molecule and how many nonbonding electron pairs are on As? |
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| Trigonal pyramid, one |
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| Which is the strongest intermolecular force? |
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| Hydrogen bonding |
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| Particles in the ___ state are held in place by their immediate neighboring particles and vibrate in place |
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| Solid |
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| Of the following, which is the weakest bond? |
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| N---N, single bond |
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| An ion contains 9 protons, 8 neutrons, and 10 electrons. Its charge is: |
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| -1 |
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| A neutral atom can be converted to a positive ion if it |
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| Loses electrons |
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| What is Avogrado's number? |
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| 6.02 x 1023 things/mole |
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Which of the following will decrease the production of ammonia?
N2(g) + 3H2(g) --> 2NH3(g) |
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| Removing hydrogen |
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| Which substance has ionic bonds between atoms? |
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| MgCl2 |
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Ammonia reacts with diatomic oxygen to form nitrogen monoxide and water in the following balanced reaction equation
4NH3 + 5O2 --> 4NO + 6H2O |
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| 3.0 |
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| The rule which helps in determining how atoms or ions combine to form compounds is known as |
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| The Octet rule |
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Name the following compounds in the order given
P2O5 SnCl4 K2CO3 |
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diphosphorous oxide tin carbide potassium (II) carbonate |
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| In which of the following does hydrogen bonding occur? |
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| NH3 |
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| Which of the following statements about the reaction diagrams is true? |
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| Reaction A proceeds faster than Reaction B |
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| If we equate "global warming" with 100,000 year temperature cycles, the main cause of "global warming" is |
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| Orbital eccentricities of the Earth and variations in the Sun's output |
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| Choose the most accurate interpretation of the chemical reaction described in the reaction diagram to the right |
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| This reaction is endergonic, absorbing heat from the environment as it proceeds |
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| Which term is used to describe a chemical compound that lowers the activation energy of a chemical reaction? |
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| Catalys |
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| In a chemical equilibrium... |
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| A chemical reaction and its reverse are occuring at equal rates |
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| The statement "if a stress is applied to a system at equilibrium, the system will adjust to relieve the stress" is known as |
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| Le Chatelier's Principle |
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| How do catalysts increase the rate of a reaction? |
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| Catalysts lower the activation energy for the reaction |
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| In an exothermic reaction, the energy of the products are ___ than that of the reactants |
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| Less |
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| Ozone is destroyed by two natural processes as presented in lecture. Which naturally occuring substances cause this destruction? |
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| Nitric oxide, hydroxyl radical |
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| The second law of thermodynamics says |
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| The total amount of entropy in the universe is constantly increasing |
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| The greatest percentage of radiation reaching the earth's surface from the sun is |
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| Infrared radiation |
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| The average temperature of the earth will most likely increase with an enhanced greenhouse effect. What is the present average temperature of the earth? |
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| 59°F |
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| Which two gases in the atmosphere do not absorb IR radiation and, thus, play no part in greenhouse warming? |
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| Nitrogen, oxygen |
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| Which change listed below would result in increased entropy (disorder of matter)? |
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| The burning of gasoline |
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| In the movie "Apollo 13", excess carbon dioxide in the air was removed by which chemical reaction? |
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| 2LiOH + CO2 --> Li2CO3 + H2O |
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| Which of the following will decrease the concentration of atmospheric carbon dioxide? |
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| Increase phytoplankton growth by adding iron, a limiting nutrient, into the ocean |
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| Choose the best and broadest interpretation for the "Annual Cycle" inset in the graph to the right |
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| Photosynthesis causes the decrease in CO2 observed from May to October |
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| Each chlorine atom in the stratosphere has the capacity to destroy how many ozone molecules? |
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| 100,000 |
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| The power source associated with the higher greenhouse gas emission is: |
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| Coal |
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| How are carbon dioxide concentrations determined from thousands of years ago? |
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| Analysis of ice samples |
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| What type of radiation from the sun accounts for the greenhouse effect? |
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| Infrared (IR) |
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| According to the documentary "An Inconvenient Truth", what are possible consequences of global warming? |
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Rising temperatures Greater number of environmental disorders Rising sea levels
(all the above) |
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| In a photochemical reaction |
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| The chemical reaction is energized by light |
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| Chemical energy is: |
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| The difference in energy calculated from the number and types of bonds in the products and reactants |
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| What is a greenhouse gas? |
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| A molecule that increases its vibrational motions when it absorbs the earth's heat energy |
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| Which of the following is not one of the four principles of Green Chemistry? |
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| Enforce laws to reduce the amount of toxic pollution released by chemical companies |
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| What does the Chapman cycle represent? |
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| The steady state production of ozone that takes place in the stratosphere |
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| What type of radiation from the sun causes the most harm to humans? |
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| UV-B |
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| Which is not a requirement for stratospheric ozone loss? |
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| UV-C light is absorbed by stratospheric oxygen |
