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CHM1020 Final Exam
Terms in this set (170)
Which one of the following is an example of a homogeneous mixture? a. a glass of pulp-free lemonade b. a carbonated beverage c. a chocolate chip cookie d. a bowl of cereal in milk
a. a glass of pulp-free lemonade
What are the 3 pillars of sustainability? a. environmental, social, economic b. diversity, efficiency, toxicity c. reduce, reuse, recycle d. equitability, justice, quality of life
a. environmental, social, economic
The quantity of .0000064 g expressed in scientific notation is....
6.4 * 10^-6 g
Which one of these materials is most likely to conduct heat? a. a chunk of phosphorous b. a titanium rod c. a sample of chlorine gas d. a silicon wafer
b. a titanium rod
Which country is the world's leading producer of rare earth elements? a. USA b. Brazil c. China D. South Africa
The analysis of the life cycle of an item starting with its raw materials and ending with the used item becoming the raw material for new products is called.. a. cradle-to-cradle b. reusability c. cradle-to-grave d. cost-benefit analysis
a. cradle to cradle
Balance this equation P4 + Cl2 --> PCl5 with the smallest whole number coefficients. Choose the answer that is the sum of the coefficients.
Of 5 major gaseous components of air, which is the only one to vary significantly in concentration from place to place and from day to day? a. nitrogen b. water vapor c. argon d. carbon dioxide
b. water vapor
Which pollutant is present in air as particulate matter? a. ozone b. soot c. sulfur dioxide d. carbon monoxide
When assessing the risk of an air pollutant, which does not play a role in considering someone's exposure to the pollutant? a. the concentration in air of the pollutant b. a person's breathing rate c. a person's lung capacity d. the toxicity of the pollutant
d. the toxicity of the pollutant
P2O5 is the chemical formula for.. a. dioxygen pentaphosphide b. diphosphorous pentoxide c. pentoxygen diphosphide d. monophosphorous pentoxide
b. diphosphorous pentoxide
Which color, as used in the Air Quality Index, warns that the level of a pollutant is hazardous, the most dangerous level? a. Maroon b. Yellow c. orange d. Green
What is the greatest source of indoor air pollution in developing countries? a. unvented space heaters b. automobiles c. cookstoves d. paint
Which 2 gases make up more than 95% of an inhaled breath? a. N2 and Ar b. NO2 and N2 c. O2 and N2 d. CO2 and O2
c. O2 and N2
There are around 2*10^22 molecules and atoms in each breath we take and the concentration of CO in the air is about 9ppm. Approximately how many CO molecules are in each breath we take?
Which pollutant are you more likely to encounter in dangerous concentrations indoors rather than outdoors? a. carbon monoxide b. nitrogen dioxide c. sulfur dioxide d. ozone
a. carbon monoxide
The EPA limit for CO is 9ppm. What is this percentage? a. .0009% b. 90% c. 9% d. 0.09%
Which substance is not considered to be an air pollutant? a. NO2 b. N2 c. O3 d. SO2
Which is the balanced chemical equation for the reaction of nitrogen (N2) with oxygen (O2) to form NO?
N2 + 02 --> 2 NO
2.3 * 10^6 is the same as ___ meters
How many protons and neutrons are in an atom of chlorine (mass number 35)? a. 18, 17 b. 17, 17 c. 17, 35 d. 17, 18
d. 17, 18
For the ionic compound NaCl, what is the charge for the sodium ion?
What is the correct answer to this problem with the correct number of significant figures? (3.2/0.123)+45.7=?
What distinguishes the atoms of one element from another? a. number of neutrons b. number of protons plus neutrons c. number of protons d. number of neutrons plus electrons
c. number of protons
Which differentiates a compound from a mixture of 2 or more elements? a. a compound is made of only 1 element b. a compound cannot be made of more than 2 elements c. the elements in a compound may not be present in varying proportions d. a compound does not exhibit the individual properties of the elements of which it is composed
d. a compound does not exhibit the individual properties of the elements of which it is composed
Which of the following is the chemical symbol for silver? a. Au b. Pb c. Ag d. Fe
Which is not a pure substance? a. sucrose b. helium c. air d. copper wire
c. air (this is a mixture)
On a periodic table, the columns of elements with similar properties are... a. groups b. periods c. rows d. metals
What term is defined as the flow of electrons from one location to another? a. electricity b. density c. resistance d. transparency
How many bromide ions can combine with 1 ion of aluminum to form an ionic compound? a. 1 b. 2 c. 3 d. 6
If we assume that the top of Mt. Everest is the highest land mass on earth, Hikers who scale its summit are standing in the ... a. mesosphere b. troposphere c. stratosphere d. ozone layer
Which component of air makes up around 100x more of an exhaled breath than of an inhaled breath? a. Ar b. O2 c. O3 d. CO2
Green chemistry is.. a. any chemistry having an agricultural base b. the study of how to improve the production of oxygen via photosynthesis c. the design of products and processes that reduce hazardous substances d. the cause of higher temperatures typically found in greenhouses
c. the design of products and processes that reduce hazardous substances
All of these pollutant can be detected by their odors except... a. NOx b. O3 c. SOx d. CO
T/F The more toxic the pollutant, the higher the concentration is set when concerning air quality standards.
How would you express .002 molecules of CO2 per hundred molecules of air as a concentration? a. 20 parts per hundred thousand b. 20 parts per million c. 2 parts per million d. 2 parts per thousand
b. 20 parts per million
The risks presented by air pollutants are a function of what things? (select all that apply) a. flammability b. exposure c. toxicity d. location
b. exposure and c. toxicity
The Air quality index is scaled from ___ to ___. a. 0-100 b. good-really bad c. 1-500 d. 1-100
Rank these substances in order of their abundance in the air you breathe from least to greatest. CO2, 03, N2, O2, Ar
O3 < CO2 < Ar < O2 < N2
Which correctly pairs an indoor pollutant with its source? a. formaldehyde and unvented space heaters b. radon and glues and solvents c. nicotine and paint and paint thinners d. O3 and electrical arching
d. 03 and electrical arching
Chapters 3 & 4
Which is correct? a. there is a dynamic steady state of ozone in the stratosphere b. ozone forms by combining an oxygen atom with an oxygen molecule c. all of these are correct d. UV radiation will dissociate ozone into an oxygen atom and an oxygen molecule
c. all of these are correct
Arrange these types of radiation in order of increasing energy per photon: gamma rays, infrared radiation, radio waves, visible light, UV
radio waves, infrared radiation, visible light, UV, gamma rays
Which region in the UV spectrum is absorbed least by the atmosphere? a. UV-C b. they're all absorbed equally b. UV-B d. UV-A
What is the role of stratospheric clouds on the destruction of ozone? a. they play no role b. chemical reactions occur on the clouds that convert molecules that do no damage to those that deplete ozone c. the clouds are made of chlorine atoms from CFCs d. the cold clouds react with ozone to make oxygen molecules and oxygen atoms
B. chemical reactions occur on the clouds that convert molecules that do no damage to those that deplete ozone
The 2 chemical bonds and geometry of water are best represented by...
2 equal length bonds
Which of the following compounds is useful for putting out fires and does not deplete stratospheric ozone concentrations? a. Methyl Bromide b. CFC-113 c. Halon-1211 d. HFCs
How do mineral nanoparticles in sunscreens protect from UV radiation? a. the particles dissolve with incoming UV light b. the particles absorb incoming UV light c. none are correct d. the particles scatter incoming UV light
b. the particles absorb incoming UV light
The structure of ozone most closely resembles a... a. bent molecule with different lengths of chemical bonds b. linear molecule with different lengths of chemical bonds c. bent molecule with same length of chemical bonds d. linear molecule with same length of chemical bonds
c. bent molecule with same length of chemical bonds
When it reaches its largest size, the ozone hole over the Antarctic is... a. about the same size as Canada b. the same size as France c. the same size as North America d. smaller than Iceland
c. the size of North America
Which atmospheric component does not contribute to global warming? a. N2 b. H2O c. O3 d. CO2
Albedo is... a. the ratio of EM radiation reflected by a surface to the amount of radiation hitting the surface b. primary wave number at which a greenhouse gas absorbs IR c. describes tendency of atmospheric molecule to react with other molecules d. describes effectiveness of a molecule as a greenhouse gas
a. the ratio of EM radiation reflected by a surface to the amount of radiation hitting the surface
Coal's formula is C135H96O9NS. Predict amount of CO2 released from combustion of 1
10^6 metric tons of coal. 1 metric ton = 1
3.11 * 10^9 kg
Although greenhouse gases likely account for the problem of global warning, they are also responsible for making earth habitable. What would be the temperature on earth in the absence of the effects of carbon dioxide and water? a. 15 C b. 450 C c. -270 C d. -18 C
d. -18 C
The internationally accepted atomic mass standard is carbon-12 because this isotope... a. is the smallest isotope that could be accurately weighed b. is the only isotope of carbon that exists c. was arbitrarily selected as a convenient standard d. is the only isotope with equal numbers of protons, neutrons, and electonrs
c. was arbitrarily selected as a convenient standard
Radiative forcings are... a. geological changes that promote volcanic eruptions b. factors that influence the balance of Earth's incoming and outgoing radiation c. changes in geographical distribution of plant, animal, and insect species brought on by climate change d. mechanisms for sequestering CO2 endorsed by signers of the Kyoto Protocol
b. factors that influence the balance of Earth's incoming and outgoing radiation
Where is most of the carbon on earth stored? a. in the form of fossil fuels and carbonate minerals and rocks b. in surface water c. in forests and soil d. in the atmosphere
a. in the form of fossil fuels and carbonate minerals and rocks
Which explanation accounts for the fact that, on average, cloudy nights are warmer than clear nights? a. clouds have a high concentration of CO2 from fossil fuel combustion b. Clouds reflect light incoming from the moon c. H2O does not absorb infrared energy d. clouds are composed of water vapor and H2O is a strong greenhouse gas
d. clouds are composed of water vapor and H2O is a strong greenhouse gas
The most abundant greenhouse gas in Earth's atmosphere is... a. CH4 b. CO2 c. H20 vapor d. N2
c. H20 vapor
How many molecules are in 20 kg of butane (C4H10)?
2.07 * 10^26 molecules
What is the frequency of light with a wavelength of 634nm?
4.73 * 10^14 Hz
How many oxygen atoms are in 6.02*10^23 molecules of ozone?
1.81 * 10^24 O atoms
Which color of visible light has the shortest wavelength? a. blue b. violet c. green d. red
A propane grill was used for 1 hour and produced 1.5 kg of CO2. What is the mass of carbon atoms produced in this amount of CO2?
What is the molar mass of the drug Flunitrazepam (C16H12FN3O3)?
HCFCs have been developed to replace CFCs as refrigerants. Which property of these new compounds makes them environmentally superior to CFCs? a. lower reactivity makes them stable even in the intense UV light in the stratosphere b. greater reactivity leads to decomposition at elevations below the stratospheric ozone concentration maximum c. they do not contain chlorine d. their higher molecular weight prevents them from reaching the stratosphere
b. greater reactivity leads to decomposition at elevations below the stratospheric ozone concentration maximum
What is the relationship between stratospheric levels of atomic chlorine and ozone? a. as chlorine changes, there is not affect on ozone level b. as chlorine increases, ozone decreases c. as chlorine changes, effect on ozone is unpredictable d. as chlorine increases, ozone increases
b. as chlorine increases, ozone decreases
DNA, the genetic material of living organisms, is damaged by light in the... a. visible region of the spectrum b. UV region, especially below wavelength of 320 nm c. UV region, especially above wavelength of 340 nm d. infrared region
b. UV region, below wavelength of 320nm
Which contributes to the ozone hole? a. automobile exhaust b. CFCs c. loss of northern forests d. all are correct
CFCs rise to the stratosphere and... a. interact with UV energy to produce free radicals that destroy ozone b. interact with UV energy to produce free radicals that react with oxygen to create ozone c. react directly with stratospheric ozone to destroy it d. react with free radicals to remove CO2
a. interact with UV energy to produce free radicals that destroy ozone
Decreased stratospheric ozone concentrations may lead to a. harm to young marine life b. increased occurrence of cataracts c. increased incidences of melanomas d. all are correct
d. all are correct
The O2 molecule breaks apart at lower wavelengths than the O3 molecule. What is the main reason for this? a. O2 is more reactive than O3 b. O3 is more reactive than O2 c. the average bond of O3 is shorter and stronger than that of O2 d. the average bond of O2 is shorter and stronger than that of O3
d. the average bond of O2 is shorter and stronger than that of O3
Which is correct? a. ozone forms by combining an oxygen atom with an oxygen molecule b. there is a dynamic steady state of ozone in the stratosphere c. UV radiation will dissociate ozone into an oxygen atom and oxygen molecule d. all are correct
d. all are correct
Which product of the UV decomposition of CFCs acts as the catalyst for ozone decomposition? a. oxygen atoms b. hydrogen atoms c. chlorine atoms d. fluorine atoms
c. chlorine atoms
The "ozone layers" is found... a. in the troposphere b. in the stratosphere c. only around the equator d. in the mesosphere
b. in the stratosphere
How much energy (in J) would a photon of green light (wavelength 532 nm) have?
3.74 * 10^19
As the wavelength of light decreases what happens to the frequency? a. cannot be determined b. stays the same c. increases d. decreases
How many lone pairs would an oxygen atom have (a single O atom)? a. 0 b. 1 c. 2 d. 3
Which of the following can cause electrons in a ground state to go to a higher level excited state? a. melanin b. heat loss c. photon absorption d. sunscreen
c. photon absorption
Any bond that involves the sharing of 2 electrons is known as a ____ bond. a. ionic b. valence c. lone pairs d. covalent
Calculate mass % of chlorine in CCl3F
In their 5th and most recent report published in 2014, the vast majority of scientists agreed on several key points. Which of the following is NOT one of these points? a. all choices were mentioned b. if rate of greenhouse gases is not curtailed, our water resources, food supply, and health will suffer c. human activities are responsible for much of recent warming d. earth is getting warmer
a. all choices were mentioned
The intergovernmental Panel on Climate Change issued a report in 2014 that attached probabilities to the predictions and statements made. Which prediction/statement was considered "Very Unlikely"?
relative to 1850-1900, the global surface temperature for the end of the 21st century will exceed 2 C
What is the effect of the absorption of infrared energy on matter? a. increases molecular radiation b. excites bonding electrons c. increases vibration of chemical bonds d. breaks chemical bonds
c. increases vibration of chemical bonds
The carbon cycle refers to the... a. frequency of light energy that affects rotational energy of CO2 b. movement of carbon through living organisms, the atmosphere, sea, and earth c. oxidation of glucose d. mechanism by which CO2 causes global warming
b. movement of carbon
How is carbon dioxide level determined? a. by extrapolating the CO2 level from temperature of ice b. by measuring CO2 concentration in trapped air bubbles in ice layers c. by extrapolating CO2 level from average global temperature d. by measuring ratio in CO2 molecules
b. by measuring CO2 concentration in trapped air bubbles in ice layers
How many molecules are present in 1kg of hydrogen gas (H2)?
3.0 * 10^26
Calculate mass of 2.5 * 10^4 molecules of nitrogen gas.
Which practices might be described as carbon sequestration? I. planting trees II. deforestation III. pumping carbon dioxide deep into the ocean IV. Increasing combustion of fossil fuels
I and III only
Which conclusion was considered "very likely" in the 2014 report of the Intergovernmental Panel on Climate Change?
human-caused emissions are the main factor causing warming since 1951
A mole of CO2 contains how many oxygen atoms?
1.20 * 10^24
What shape would a molecule of carbon tetrachloride have? a. tetrahedral b. bent c. trigonal planar d. trigonal pyramid
When a molecule absorbs an infrared photon it contributes to the ____ energy of that molecule. a translational b. rotational c. vibrational d. cannot be determined
Which atom in a molecule of CH3Cl would contain the partial negative charge? (relates to electronegativity)? a. hydrogen b. chlorine c. carbon d. cannot be determined
Ozone is important in our atmosphere because it a. reflects IR radiation b. reacts with excess CO2 c. absorbs some UV radiation d. helps trees grow
c. absorbs some UV radiation
During the Antarctic spring, ozone is destroyed at a greater rate than it is formed... a. in a process that is catalytic b. on the surface of atmospheric ice crystals c. in polar stratospheric clouds d. all are correct
d. all are correct
Which is NOT a likely consequence of increased carbon dioxide concentration in the atmosphere? a. changes in ocean chemistry b. sea ice disappearance c. increase in biodiversity d. sea-level rise
c. increase in biodiversity
Every increase of on pH unit indicates a. 10 times more hydrogen ions in solution b. an increase in acidity c. none of these are correct d. 10 times less hydrogen ions in solution
d. 10 times less hydrogen ions in solution
The face that carbon is less electronegative than Nitrogen means that in a C-N bond, the... a. shared electrons are closer to the N than to the C atom b. C atom takes the electrons from the N atom forming C- and N+ c. shared electrons are closer to the C atom than to the N atom d. N atom takes the electrons from the C atom forming C+ and N-
a. shared electrons are closer to the N atom than to the C atom
How many moles of sodium chloride are there in 250mL of a 1.20 M sodium chloride solution?
The pH of lemon juice is around 2.40. At this pH, the hydronium ion concentration is closest to which concentration?
4.0 * 10^-3 M
The recommended daily requirement of calcium is 1000mg. Tap water in a city contains around 150mg Ca/L. A person living in the city who drinks 2 liters of water in 1 day would receive ___% of their RDA of calcium.
What is the molarity of sodium chloride in a solution containing 0.5 mol fo sodium chloride in 500mL of water?
Lakes surrounded by ___ have very little acid-neutralizing capacity. I. Marble II. Granite III. Limestone
II only Granite
Which solution is acidic? a. MOH-=0.0065 M b. MOH-=1.77
10^-10 M c. MH+=1.27
10^-9 M d. MH+=5.79*10^-10 M
b. MOH-=1.77*10^-10 M
Which concentration is consistent with a basic solution? a. MH+=3.2
10^-3 M b. MOH-=3.4
10^-3 M c. MH+=9.7
10^-4 M d. MOH-=3.6
Which reaction accounts for the fact that the pH of rain is naturally slightly acidic?
CO2 + H2O --> H+ + HCO3-
A student wants to prepare exactly 250mL of a .500 M aqueous potassium hydroxide solution. What mass of potassium hydroxide (molar mass =56.10 g/mol) must the student dissolve in the 250 mL of solution?
When dissolved in water, hydrogen bromide forms hydrobromic acid. Determine the hydroxide ion concentration in a 4500mL solution containing 3.78g hydrogen bromide; Kw = 1.00 * 10^-14
[OH-]= 9.63 * 10^-13 M
Evaluate the ratio MH+ (pH 3) / MH+ (pH 7)
Which form of water disinfection continues to provide antibacterial protection after the water leaves the purification plant? a. chlorination b. ozonation c. UV radiation d. filtration
Bases produce which ions in aqueous solution? a. OH- b. Cl- c. SO3- d. NO2-
In general, hydrogen bonds are... a. about 10 times stronger than typical covalent bonds b. about 1/10 as strong as typical covalent bonds c. found only between H atoms in molecules like H2 d. found in every molecule containing more than one hydrogen atom
b. about 1/10 as strong as typical covalent bonds
Which compound is insoluble in water? a. calcium carbonate b. ammonium chloride c. potassium nitrate d. sodium carbonate
a. calcium carbonate
Why is water a liquid at room temperature instead of a gas? a. water has hydrogen bonds between the molecules b. water is a good solvent c. water is very acidic d. it is a gas at room temperature
a. water has hydrogen bonds between the molecules
A polar covalent bond is created when... a. a metallic element reacts with a nonmetallic element b. 2 atoms share their bonding electrons unequally c. 2 atoms share 3+ electrons d. 2 atoms of the same element form double or triple bonds
b. 2 atoms share their bonding electrons unequally
When the ___ molecules of ethanol (C2H5OH) are added to water, the ethanol molecules ____ a. polar; form covalent bonds with the polar water molecules b. polar; form hydrogen bonds with the polar water molecules c. nonpolar, are not attracted to the polar water molecules d. nonpolar; are attracted to the nonpolar water molecules
b. polar; form hydrogen bonds with the polar water molecules
Rank the following solutions in order of increasing concentration: I. 32.3g of NaCl in 100mL of water II. 0.10 mol of NaCl in 10 mL of water III. 62.1 g of NaCl in 1 L of water IV. 0.25 M NaCl solution
d < c < a < b
50 g of CuCl2 was placed in a volumetric flask and filled with water to the 500mL mark. What is the concentration of the solution in molarity?
Which of the following molecules are polar? I. H2S II. CO2 III. BCl3 IV. H2O
I and IV
If you weight out 65 g of silver nitrate (AgNO3) and add enough water to make 3 L of solution, what is the molarity of the solution?
A sample of hard water has a Ca2+ concentration of 135ppm. What is the concentration in units of molarity?
3.37 * 10^-3 M
Which of these is not a trihalomethane? a. CHF3 b. CHCl3 c. CHBr2Cl d. CH3Cl
Which is the best definition of specific heat?
a. quantity of heat energy that must be absorbed to increase the temperature of 1g of a substance 1 degree Celsius
Which of the following is not carried out by bacteria in soil? a. atmospheric nitrogen is fixed in soils b. ammonium is converted into nitrites c. all of these are carried out by bacteria d. nitrites are converted to nitrates
c. all of these
When table sugar dissolves in water, which types of attraction between water and sugar molecules occur? I. hydrogen bonding II. polar-polar interactions III. covalent bonding
I and II only
Which chemical equation shows the dissociation of 2 protons from trihydrogen phosphate?
H3PO4 --> 2H+ + HPO4-
Which substance has the highest pH? a. rain b. a lye solution c. a sulfuric acid solution d. orange juice
b. a lye solution
An acidic fog in Pasadena was found to have a pH of 2.50. Which expression represents this pH measurement? a. MH+=2.5 M b. MOH-= 3.2
10^-9 M c. MH+= 9.7
10^-3 M d. MOH-=3.2 * 10^-12 M
d. MOH-=3.2*10^-12 M
What is biological oxygen demand (BOD)? a. a measure of the amount of dissolved oxygen necessary to purify wastewater b. a measure of the phosphate ion concentration of water c. a measure of the amount of dissolved oxygen microorganisms use up as they decompose organic wastes found in water d. a measure of nitrate ion concentration of water
c. a measure of the amount of dissolved oxygen microorganisms use up as they decompose organic wastes found in water
The bond between the 2 nitrogens in N2 gas is a ___ a. strong bond dipole b. polar covalent bond c. ionic bond d. nonpolar covalent bond
d. nonpolar covalent bond
For a molecule to exhibit hydrogen bonding the H can be covalently bonded to... ? a. phosphorous b. nitrogen c. carbon d. sodium
What percentage of water on earth is freshwater?
How much acetic aci d (CH3COOH) in grams, would be required to make 1 L of a 1.5 M acetic acid solution in water?
What is the pH of a .001 M HNO3 (a strong acid) solution?
A gasoline's octane rating is a measure of the... a. energy content of the gasoline b. purity of the gas c. pollutants produced by burning the gas in the vehicle's engine d. gas's resistance to causing knocking in a vehicle's engine
D. gas's resistance to causing knocking in a vehicle's engine
The process by which a solution is heated to its boiling point and the vapors are condensed and collected is known as... a crystallization b. distillation c. cracking d. combustion
A chemical reaction accompanied by a release of eenrgy is called a ___ reaction. a. fast b. exothermic c. endothermic d. catalyzed
Advertising claims sometimes state that adding something mechanical to a car's engine will allow it to recover 100% of the energy that comes from burning gas. You should be skeptical of such claims because they violate the... a. law of conservation of matter b. activation energy requirements of all chemical reactions c. second law of thermodynamics d. first law of thermodynamics
c. second law of thermodynamics (no process can be 100% efficient due to entropy)
How is heat energy used to generate electricity in a modern power plant? a. heat warms wires causing electrons to move through them more rapidly b. heat generates strong magnetic fields through which the wires of a turbine move c. heat warms the fins on a turbine, causing them to spin d. heat boils water to make steam, which drives a turbine
d. heat boils water to make steam, which drives a turbine
Which of these statements about biodiesel is not true? a. biodiesel is nontoxic and biodegradable b. biodiesel has been withdrawn from several states due to health concerns c. biodiesel can be used in diesel engines without major modifications d. biodiesel is made from renewable resources like vegetable oils and animal fats
b. biodiesel has been withdrawn from several states due to health concerns
Which of the following is not a drawback of using coal for energy production? a. mining explosions b. mercury in fly ash c. difficult transportation due to instability d. mountaintop mining
c. difficult transportation due to instability
In a solar cell, semiconductors of the p-type and n-type are placed in contact with each other via conducting wire. In order to generate an electric current, which of the following must be true? a. light shining on the system will cause oxidation to occur b. light shining on the system must have enough energy to set electrons in motion from the n-type to p-type semiconductors c. light shining on the system must have enough energy to set electrons in motion from the p-type to n-type semiconductors d. an external battery must be attached
b. light shining on the system must have enough energy to set electrons in motion from the n-type to p-type semiconductors
What type of radiation is given off in a nuclear reaction that produces an element with 1 less proton? a. beta b. gamma c. neutron d. alpha
N-type semiconductors are associated with... a. flow of electrons b. flow of holes
a. flow of electrons
Approximately what % of electrical energy generated in the US is produced from nuclear energy? a. 50% b. 10% c. <2% d. 20%
If you have 200g of radioisotope with a half-life of 5 days, how much isotope would remain after 15 days? a. 12.5g b. 13.3g c. 40.0g d. 25.0g
Semiconductors, such as the element silicon, may be used in cells that convert solar radiation to electricity. One of the major difficulties encountered in using silicon is that it... a. is one of the rarest of all elements and therefore difficult to find on earth b. is expensive to produce large quantities of extremely pure silicon c. quickly evaporates when isolated in a pure state d. is most active of all elements, so cannot be prepared in a pure state
b. is expensive to produce in large quantities of extremely pure silicon
Which of these locations would be most likely to use electricity generated by hydroelectric power? a. Washington b. Venezuela c. Kentucky d. Russia
The "doping" of a semiconductor to improve its performance means... a. slightly raising the temperature of a pure semiconductor to improve the ability of its electrons to flow from atom to atom b. mixing large amounts of a metal with small amounts of a semiconductor so that the metal becomes a semiconductor c. adding small amounts of other elements to the pure semiconductor to change the freedom of electron motion throughout the crystal d. fusing layers of 2 different pure semiconductors together to give the electrons that absorb the solar radiation characteristics of the electrons of both semiconductors
c. adding small amounts of other elements to the pure semiconductor to change the freedom of electron motion throughout the crystal
Which type of renewable energy has most commonly been adapted for use on an individual basis? a. photovoltaic b. wind c. hydroelectric d. biodiesel
A Big Mac has a nutritional value of 563 Calories. Express this value in joules. (1 Cal = 1000 cal, 1 cal = 4.184J)
2.36 * 10^6 J
John ate a whole pizza which has 2368 Cal. If he burns 125 Cal by walking for 30 minutes, how long would it take to burn off the entire pizza by walking?
9 hours and 28 minutes
A hot dog has nutritional value of 290 Cal. How many 20kg dumbbells could be lifted 1m off the floor with the amount of energy obtained from metabolizing 1 hot dog? (It requires 200J of energy to life a 20kg dumbbell 1m off the floor (1 Cal = 1000 cal, 1 cal = 4.184J)
Assume that coal can be represented by the chemical formula C135H96O9NS. If 15 tons of coal is burned, what mass of sulfur is formed in the SO2 produced by this process?
A Big Mac has nutritional value of 563 Calories. Assuming that all energy produced goes towards keeping your heart beating, how many days can the Big Mac sustain a heartbeat of 82beats/minute? (1 Cal = 1000 cal, 1 cal = 4.184J, 1 heartbeat requires 1J of energy)
The heat of combustion for n-heptane is 4187 kJ/mol. How much heat is produced if 200kg of n-heptane (C7H16) is completely combusted?
8.36 * 10^6 kJ
The energy of motion is called ___ energy.
Which of the following is a proper use for a calorimeter? a. measuring the temperature of a mixture b. measuring amount of oxygen consumed in a combustion reaction c. measuring entropy of a reaction d. measuring heat of combustion
d. measuring heat of combustion
In a refinery, the components of petroleum are separated by... a crystallization b. combustion reactions c. fractional distillation d. isomerization
c. fractional distillation
Why is the mileage a vehicle gets less when burning E85 than 100% gasoline? a. It is not, E85 gives better mileage per gallon burned b. Ethanol has a lower heat of combustion c. It is not, they are the same D. Ethanol has higher heat of combustion
b. ethanol has a lower heat of combustion
The energy stored in the chemical bonds of fossil fuels is a form of ___ energy.
If 1.8 * 10^14 J is released in a nuclear reaction, how much matter was lost?
2.0 * 10^-3 kg
As of 2007, what is the maximum efficiency of a multijunction solar cell? a. 80% b. 40% c. 15% d. 22%
Silicon doped with gallium would be an example of a...
What is the atomic number of Pt-175 after it undergoes alpha decay?
Rank the hydrocarbons below in order from lowest to highest boiling point. Pentane, Octane, propane, methane
methane < propane < pentane < octane
energy of products is greater than energy of reactants
energy of reactants is greater than energy of products
Which of the following is not a "clean coal" technology already in use?
Sequestration to capture and store CO2 before it's emitted into the atmosphere
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