Chemistry Exam 3

The combustion of one gallon of gasoline releases ______ pounds of CO2 into the atmosphere.

19.4 pounds of CO2

Flourine is the most reactive nonmetal on the periodic table. In the presence of fluorine, iron will ignite and reactive metals such as potassium will explode. Fluorine produces compounds with nearly all of the nonmetals, including some of the Nobel gases. Balance the following representative reactions: A. Fe(s) + F2(g)  FeF3(s) B. K(s) + F2(g)  KF(s) C. S8(s) + F2(g)  SF4(g) D. S8(s) + F2(g)  SF6(g) E. Xe(g) + F2(g)  XeF6(s) F. Kr(g) + F2(g)  KrF4(s)

A. 2 Fe(s) + 3 F2(g)  2 FeF3(s) B. 2 K(s) + F2(g)  2 KF(s) C. S8(s) + 16 F2(g)  8 SF4(g) D. S8(s) + 24 F2(g)  8 SF6(g) E. Xe(g) + 3 F2(g)  XeF6(s) F. Kr(g) + 2 F2(g)  KrF4(s)

Write a balanced chemical equation for the combustion of each of the following: A. C3H8 B. C6H14

A. C3H8 + 5 O2 → 3 CO2 + 4 H2O B. 2 C6H14 + 19 O2 → 12 CO2 + 14 H2O

You were a pretty good basketball player in high school. You decide to participate in a fund raising effort for a worthy cause which requires you to compete at making free throws. How would you explain your effort in terms of precision and accuracy if: A. You made 98 out of 100 of your free throws? B. You made 21 free throws, the rest bounced off or entirely missed the rim? C. You swished 3, the other 97 hit the front of the rim and bounced back?

A. High precision and high accuracy. B. Low precision and poor accuracy. C. High precision but poor accuracy.

19. Different forms of light energy interact with molecules in different ways. Identify each form of electromagnetic radiation that cause each of these different types of quantum mechanical excitations. A. Molecular rotations absorb ___________. B. Vibrating chemical bonds absorb ___________. C. Electrons absorb ___________. D. Chemical bonds can be broken by ___________.

A. Molecular rotations absorb microwaves. B. Vibrating chemical bonds absorb infrared light. C. Electrons absorb visible light. D. Chemical bonds can be broken by ultraviolet light.

The term "Chinese" people can be misleading because China unites a relatively diverse group of distinct nationalities under one central government. A. What is the largest nationality in China? B. What percentage are minority nationalities?

A. Most Chinese people belong to the Han Nationality. B. Approximately 7% belonging to numerous ethnic minority nationalities.

Nonmetal oxides react with water to form acids. Balance the following reactions showing the formation of sulfuric acid, nitric acid, and phosphoric acid. A. SO3 + H2O  H2SO4 (sulfuric acid) B. N2O5 + H2O  HNO3 (nitric acid) C. P4O10 + H2O  H3PO4 (phosphoric acid)

A. SO3 + H2O  H2SO4 (sulfuric acid) B. N2O5 + H2O  2 HNO3 (nitric acid) C. P4O10 + 6 H2O  4 H3PO4 (phosphoric acid)

Clearly explain the following two terms: A. The atmospheric "greenhouse effect." B. The "enhanced greenhouse effect."

A. When sunlight encounters the earth's atmosphere, some is reflected. Most sunlight, though, passes through the atmosphere. When this light strikes the Earth's surface, it is either reflected or absorbed. On average, about half of all solar radiation is absorbed by the Earth's surface. The warm earth, in turn, radiates the absorbed energy back into space as infrared light. Infrared radiation emitted from the Earth's surface can be absorbed by greenhouse gases such as carbon dioxide, methane, and water in our atmosphere, creating the "greenhouse effect". B. The "enhanced greenhouse effect" is the result of the buildup of excess greenhouse gases in our atmosphere which is causing the atmosphere to warm above normal temperatures.

Name each of the following hydrocarbons. A. CH4 B. C3H8 C. C5H12 D. C8H18

A. methane B. propane C. pentane D. octane

Complete the following sentences: A. Accuracy refers to how close a measurement is to ______________________. B. Precision refers to how close a measurement is to ______________________.

Answer: A. Accuracy refers to how close a measurement is to the actual value. B. Precision refers to how close a measurement is to other measurements in the series.

Arenal is an active volcano. About how often does it experience a major eruption?

Arenal averages about one major eruption every 400 years

Approximately how much have average global temperatures increased since record keeping began in 1880.

Average global temperatures have increased by about 0.8 oC (1.5 oF)

Sucrose (table sugar) is a carbohydrate. Balance the chemical equation showing the metabolism of sucrose, C12H22O11, to form carbon dioxide and water. C12H22O11 + O2  CO2 + H2O

C12H22O11 + 12 O2  12 CO2 + 11 H2O

What does "COP 18" refer to?

COP 18 refers to the UNFCCC 18th Conference of Parties. The annual COP serves as the UNFCCC supreme body, given the "highest decision-making authority."

State Ionic or Covalent and then the name of the compound CaCO3 SO3 Mg3(PO4)2 N2O4

CaCO3-ionic-calcium carbonate SO3-covalent-sulfur trioxide Mg3(PO4)2-ionic-magnesium phosphate N2O4-covalent-dinitrogen tetraoxide

State Ionic or Covalent and then the name of the compound CaO NO MgCl2 S2Cl2

CaO-ionic-calcium oxide NO-covalent-nitrogen monoxide MgCl2-ionic-magnesium chloride S2Cl2-covalent-disulfur dichloride

Write the chemical formula for each of the following compounds: Carbon monoxide Dinitrogen monoxide Potassium nitrate Sodium phosphate

Carbon monoxide-CO Dinitrogen monoxide-N2O Potassium nitrate-KNO3 Sodium phosphate-Na3PO4

What is meant by the term "carbon neutral"?

Carbon neutral refers to achieving net zero carbon emissions of CO2 by balancing the amount of carbon released with an equivalent amount of carbon sequestered, or offset.

Which country is the largest greenhouse emitter

China

Which country is the leading greenhouse gas-producing nation?

China

The figure below displays the total megatons of CO2 emitted by country for 2011. Compare and contrast this graph with Figure zz in Chapter 4 which gives per capita CO2 emissions by country for 2011.

China is the world leader in CO2 emissions. However, it is a populous nation; therefore, the emissions per person is relatively low. By contrast, Qatar as a nation emitted a paltry 79 megatons of CO2 as a nation in 2011. Even though each individual emits an outsized quantity of CO2, its low total emissions total is due to its small population.

What has been the major driver to ice age cycles throughout geological time periods on Earth?

Complex variations in Earth's orbit have altered the balance and distribution of solar radiation on the surface of our planet driving the ice age cycles.

List at least three compounds that might be found in volcanic gases.

Compounds such as sulfur dioxide, carbon dioxide, carbon monoxide, hydrogen chloride, hydrogen fluoride, and water vapor are commonly found in volcanic gases.

Energy" is defined as _________________.

Energy is defined as the "ability to do work."

What are the three primary fossil fuels?

Fossil fuels exist primarily in the form of coal, natural gas, and petroleum.

Write the correct chemical formula for each of the following gases which may be found in the plume of a volcanic eruption. Hydrogen sulfide Hydrogen fluoride Carbon dioxide Hydrogen fluoride Carbon monoxide Sulfur dioxide

Hydrogen sulfide-H2S Hydrogen fluoride-HF Carbon dioxide-CO2 Hydrogen chloride HCl Carbon monoxide CO Sulfur dioxide SO2

How does a balanced chemical equation relate to the Law of Conservation of Mass?

In a balanced chemical equation, the total number of reactant atoms must equal the total number of product atoms. Since the identity of each element does not change in a chemical reaction, this dictates that its mass does not change in a chemical reaction. Thus, the total number of atoms and mass on the reactant side equals the total number of atoms and mass on the product side. Mass is conserved in a chemical reaction.

While CO2 is the main greenhouse gas you read and hear about contributing to global warming, another gas being hailed as "cleaner" burning and a "transition" fuel is _________, this gas has a global warming potential that is _________ times greater than CO2.

Methane or CH4 has a global warming potential 21 times greater than that of CO2.

What are Milankovitch Cycles?

Milankovitch Cycles are complex variations in Earth's orbit, tilt, and wobble that converge in cycles.

Deng Xiaoping instituted market reforms in China after the Cultural Revolution, stating "Weather a cat is black or white makes no difference. As long as it catches mice, it is a good cat." What was he suggesting by this statement?

Mr. Deng was a pragmatist who noted that "poverty is not socialism." He successfully maintained a balance between a market economy which provided prosperity and a strong central Communist Party which maintained government control.

Which country is the largest per capita greenhouse gas emitter?

Qatar

Write the chemical formula for each of the following compounds: Silicon tetrafluoride Sodium bicarbonate Magnesium hydroxide Chlorine pentafluoride

Silicon tetrafluoride-SiF4 Sodium bicarbonate-NaHCO3 Magnesium hydroxide-Mg(OH)2 Chlorine pentafluoride-ClF5

What did Roger Revelle mean when he stated, "Human beings are now carrying out a large scale geophysical experiment of a kind that could not have happened in the past nor be reproduced in the future."

Since the onset of the Industrial Revolution, the human race has been burning fossil fuels at an alarming rate. It took half a billion years of geologic history to store this terrestrial carbon (coal, petroleum, and natural gas) which we are now returning to the atmosphere as CO2. This rate of return has never happened in the past. Considering the millions or billions of years that will be required to replenish these fossil fuels, it is unlikely that humans will be around to conduct this global geo-experiment again in the future.

What was the Chinese Cultural Revolution? When did it end?

The Chinese Cultural Revolution was decade-long period—from 1966-1976—of widespread political and social chaos. During this decade, Chairman Mao Zedong embarked on a campaign to root out all "enemies of the people." It was a brutal period, gripping the nation in a pervasive climate of fear and deceit, waste and destruction, famine and starvation, and torture and death. The Cultural Revolution ended with Mao's death in 1976.

What was the warmest decade on record?

The decade beginning with January 2000 and ending with December 2009 was the warmest decade on record.

When was the last major eruption of Arenal volcano?

The last major eruption occurred in July 1968. Author's note: There have been some sizeable eruptions since, most notably in 1998, but they were small in comparison to the 1968 blast.

What were the "three rounds and a sound" that defined prosperity during the period shortly after the Cultural revolution?

The three rounds were a bicycle, a watch, and a sewing machine. The sound was a radio.

Was there any warning that Arenal might be on the verge of erupting?

The timing of the eruption was unexpected. However, it was not without warning. As much as two weeks prior to the eruption, cows were observed moving down from pastures on the upper slopes; the water level of a nearby lake dropped, resulting in numerous fish deaths; there was an increase in water temperature of surrounding hot springs, and creek waters changed their taste. Some villagers elected to ignore these ominous warnings.

What were the three warmest years on record?

The year 2010 is ranked as the warmest year on record, followed by 2005 and 1998.

The isotope U-235 must be separated from other uranium isotopes for use in nuclear reactors. One step in nuclear reprocessing requires uranium to be converted to volatile UF6. Balance the equation for this process. U(s) + ClF3(g)  UF6(g) + Cl2(g)

U(s) + 2 ClF3(g)  UF6(g) + 3 Cl2(g)

What is the UNFCCC?

UNFCCC refers to "The United Nations Framework Convention on Climate Change". The UNFCCC was created at the 1992 "Earth Summit" in Rio de Janeiro, Brazil, with the aim of "preventing dangerous human interference with the climate system." The U.S. joined more than 150 nations in signing the convention.

What are the two primary natural radiative forcings that are not the result of human activities—responsible for climate change?

Volcanic eruptions and solar variation.

Are Arab countries at risk due to climate change?

Yes. A World Bank Report released at COP 18 warned that temperatures in the Arab world are increasing 50% faster than the global average. Climate disasters have already affected 50 million Arab individuals in the last 30 years, and immediate action is needed to avoid the risk of increased water shortages and food insecurity.

Write the chemical formula for the binary ionic compound that can be formed from each pair of elements: a. Al and O b. Ba and Cl c. K and S d. Mg and N

a. Al2O3 b. BaCl2 c. K2S d. Mg3N2

All of the following equations represent common combustion reactions. Balance each of these equations. a. Combustion of natural gas (methane, CH4) CH4(g) + O2(g)  CO2(g) + H2O(g) b. Combustion of LPG (liquid propane gas, C3H8) C3H8(g) + O2(g)  CO2(g) + H2O(g) c. Combustion of butane in a lighter (C4H10). C4H10(g) + O2(g)  CO2(g) + H2O(g) d. Combustion of ethanol (C2H6O). C2H6O (l) + O2(g)  CO2(g) + H2O(g)

a. CH4(g) + 2 O2(g)  CO2(g) + 2 H2O(g) b. C3H8(g) + 5 O2(g)  3 CO2(g) + 4 H2O(g) c. 2 C4H10(g) + 13 O2(g)  8 CO2(g) + 10 H2O(g) d. 2 C2H6O (l) + 7 O2(g)  4 CO2(g) + 6 H2O(g)

The name provided for each of the following compounds contains an error. Find the error and then provide the correct chemical name. a. CS2 monocarbon disulfide b. Li2O dilithium monoxide c. NH4Cl nitrate chloride d. Na2SO4 disodium sulfate

a. CS2 monocarbon disulfide; carbon disulfide b. Li2O dilithium monoxide; lithium oxide c. NH4Cl nitrate chloride; ammonium chloride d. Na2SO4 disodium sulfate; sodium sulfate

Write the chemical formula for the ionic compound that can be formed from each pair of ions: a. Na1+ and PO43- b. NH41+ and S2- c. Mg2+ and OH1- d. Ca2+ and CO32-

a. Na3PO4 b. (NH4)2S c. Mg(OH)2 d. CaCO3

Which elements in the periodic table are found in a. hydrocarbons ____________? b. carbohydrates _____________?

a. hydrocarbons contain C and H b. carbohydrates contain C, H, and O

Is breaking of chemical bonds an endothermic or exothermic reaction.?

endothermic

Is energy released or absorbed when a bond forms?

released