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CHM 1020 Chapter 3

Terms in this set (83)

The bond angle for a tetrahedral molecule (such as CH4) is equal to
109.5 degrees
Which of the following options correctly interpret the information provided by the balanced equation CH4 + 2O2 --> CO2 + 2H2O
----1 mole of CH4 produces 1 mole of CO2 when reacted with 2 moles of O2
---15 mol of CH4 will produce 15 mol of CO2 when burned completely in O2.
---1 molecule of CH4 reacts with 2 molecules of O2.
Match each element in the compound NH3 to its correct mass ratio and mass percentage
Mass ratio of N= .824
Mass percent of N= 82.4
Mass ratio of H= .176
Mass percent of H= 17.6
nonbonding electron pairs are also referred to as
Lone pairs
Correctly order the steps required to determine the shape of a molecule, starting with the first step at the top of the list
1.) Determine the number of outer electrons associated with each atom in the molecule
2.) Arrange the outer electrons in pairs, ensuring that all atoms other than hydrogen obeys the octet rule.
3.) Count the groups of outer electron pars to predict the shape.
Which of the following statements correctly describe the mole?
---One mole of any substance contains 6.02X 10>23 particles.
---The number of particles in a mole is called Avogadro's number.
All atomic masses are determined relative to the mass of an atom
carbon-12
For any element, the atomic mass recorded on the periodic table is not a whole number since it is a ____ of the masses of its naturally occurring isotopes.
average
Match each compound correctly to its molar mass. (round all atomic masses read from the periodic table to one place after the decimal)
CCl>4 -------- 154.0 G
PF>3 --------- 88.0 G
SO>2 ---------- 64.0 G
The most stable molecular arrangement is the one in which the ____ electron groups are as far apart as possible, to minimize electron-electron ____.
Outer, repulsion
Which of the following options correctly interpret the information given? Molar mass of NO>2 = 46.0g; atomic mass of nitrogen = 14.0g; atomic mass of oxygen = 16.0g
--- There are 14.0g of nitrogen in every 46.0g of NO>2
--- The percentage oxygen in NO>2 is equal to 32.0/46.0 X100
--- The mass ratio of nitrogen is NO>2 is equal to .304
The production of nitric acid(HNO>3) is closely linked to the manufacture of fertilizers, and it is estimated that 60 million tons of this substance was produced worldwide in 1999. What is the mass of nitrogen in this quantity of nitric acid.
--- 13 million tons
(60 million tons HNO>3 X 14.0gN/63.0g HNO>3)
Which of the following statements correctly describe molar mass?
---The molar mass of a molecular substance is the mass per mole of its molecules.
--- The periodic table can be used to calculate the molar mass of any substance.
--- The molar mass of oxygen is 16.0 g. This means that 1 mole of oxygen atoms has a mass of 16.00g.
There are exactly _____X 10^23 atoms in 12g of carbon-12 (given to two places after the decimal). This number is called ____ number.
6.02
Avogadro's
Consider the balanced equation 2H>2 + O>2 --> 2H>2O. The coefficients (number in front of the formulas) correspond to the number of particles of each substance involved in the reaction, which is proportional to the ____ of each substance.
Number of moles
Which of the following options correctly relate the number of outer electron groups in a molecule to its observed shape?
--- A linear shape is observed for a molecule with two bonding electron groups and no lone pairs
--- A molecule with two bonding and two nonbonding electron pairs will be bent
The molar mass of CH>2Cl>2 is85.0g. While the atomic mass of carbon is 12.0g. The mass ratio of carbon in this compound is correctly expressed as:
12.0g C/ 85.0 g CH>2Cl>2
The molar mass of any substance is the mass of 1 _____ of the particles of that substance
Mole
Match each forcing with the effect it has on global temperatures on Earth.
Increasing atmospheric CH>4 ------ Causes a warming effect
Increasing cloud cover -------- Causes a cooling effect.
An example of a positive forcing ----- Increasing levels of GHGs in the atmosphere
An example of a negative forcing ---- Increasing levels of aerosols in the troposphere
The atomic mass of an element is the mass in grams of the same number of atoms found in exactly 12 g of _____-12
Carbon
Match the number of outer election groups correctly to the molecular shape observed.
4 bonding pairs ---- tetrahedral
3 bonding pairs and 1 lone pair ---- trigonal pyramidal
2 bonding pairs ---- linear
2 bonding pairs and 2 lone pairs ---- bent
3 bonding pairs --- trigonal planar
Which of the following are examples of fossil fuels
coal
petroleum
natural gas
Place the following greenhouse gases in order of decreasing global warming potential. Start with the gas that has the lowest GWP at the bottom of the list.
N>2O
CH>4
CO>2
Which of the following options correctly describe the underlying principle used to determine molecular shape from a Lewis structure?
Each group of outer electrons around a central atom is located as far from the others as possible.
Which of the following options correctly describe the changes observed in global temperature over time? Select all that apply.
The average global temperature of the Earth has increased over the past century.
The average global temperature has increased over the same period as atmospheric CO>2 levels have increased.
The proportion of incoming radiation that is reflected by a surface is called the ____. This quantity is a measure of the reflectivity of a surface.
Albedo
Match each type of radiation to the effect it has on a molecule
IR radiation --- Causes the molecule to vibrate
UV radiation --- Breaks bonds, causing the molecule to dissociate
Microwave --- Causes the molecule to spin faster
The global warming ___ (GWP) of a greenhouse gas represents the relative contribution of a given atmospheric gas to global warming.
Potential
Which of the following options correctly compare climate change with ozone depletion?
---Greenhouse gases absorb IR radiation, which is not involved in ozone depletion.
---These two processes are linked though the production of CFC's.
--- These two atmospheric processes occur in different parts of the atmosphere
Among other effects, climate change is expected to cause ___ weather along with a changed climate.
More extreme
Any gas that can absorb _____ radiation can act as a greenhouse gas.
Infrared
Which of the following is NOT a greenhouse gas?
N>2
N>2O
O>3
NO
N>2
Contrast weather and climate
Weather- describes events of relatively short duration, including daily high and low temperatures.
Climate - Describes regional events recorded over longer periods.
Which greenhouse gases were specifically targeted by the Kyoto Protocol?
hydrofluorocarbons
CO>2
N>2O
Carbon ____ and ____ strategies (CCS) involve the separation of CO>2 from other combustion products and storing it in geologic locations.
capture
storage
Carbon capture and storage strategies
What was the role of the IPCC (International Panel on Climate Change), established in 1988?
The IPCC was to assess both scientific and socioeconomic data relating to climate change.
Which of the following options correctly describe the "cap-and-trade" system for reducing greenhouse gas emissions?
--- A company that produces less CO>2 may trade its excess allowances to another company
--- A "cap" or upper limit is set for the emissions from the industries run by a given company
--- Companies may trade their annual allowances with each other.
Match each source of atmospheric methane (CH>4) to the process by which methane is formed and/or released into the atmosphere.
Wetlands and landfills--- CH>4 is produced from the decomposition of organic matter by anaerobic bacteria.
Oceans--- CH>4 may be released from methane hydrates due to drilling.
Farming--- CH>4 produced in the digestive systems of cattle and sheep is released to the atmosphere.
Fossil fuels--- CH>4 found together with oil and coal deposits is released by drilling and mining.
A gas that is able to absorb and trap infrared radiation, resulting in a warming of the atmosphere, is called ____ gas.
Greenhouse
Which of the following options correctly describe the interaction of a molecule with IR radiation?
--- IR radiation can excite both bending and stretching vibrations.
---The wavelengths of IR radiation absorbed depends on the structure of the molecule
--- IR radiation causes the bonds in a molecule to vibrate in various ways.
Ice core data shows that atmospheric CO>2 levels ____.
Were relatively constant from the beginning of the last millennium until around 1800
The process by which atmospheric gases trap and return more than 80% of the heat energy radiated by Earth is called the ____ greenhouse effect, resulting in an increase in average global temperatures.
enhanced
Ozone is able to act as a greenhouse gas because its ____ shape allots it to vibrate in ways that involve ____ in overall charge distribution.
bent
a change
Which one of the following statements best describes a molecule that can absorb IR radiation?
Its bond vibrations must involve a change in charge distribution.
In order for a molecule to absorb IR radiation, the energy of the IR radiation must ___.
match one of the vibrational energy modes of the molecule.
In order to predict if a given molecule can act as a greenhouse gas, we must use its Lewis structure to determine its molecular ____.
Shape
Which of the following were determined to be very likely by the IPCC in 2007?
--- Higher maximum temperatures are observed over nearly all land areas compared to records from a century ago.
--- Human activities are the main factor that has caused warming since 1950
--- Snow and ice cover have both decreased measurably on the Earth.
In general, a lone pair occupies ___ space than a bonding electron pair, and will therefore ___ the bond angle between bonding pairs.
More
decrease
Which of the following options correctly explain how carbon-14 levels can provide information about the source of atmospheric CO>2?
CO>2 produced by burning fossil fuels causes the carbon-14 concentration in the atmosphere to decrease
CO>2 produced by burning of fossil fuels contains virtually no carbon-14
An estimate of the amount of CO>2 and other greenhouse gas emissions produced by an individual in a given time frame is referred to as that individual's carbon ____.
footprint
Match each solar body with the primary type of radiation it emits
Earth -- Infrared radiation
Sun -- Ultraviolet, visible, and infrared radiation
Which of the following processes release CO>2 into the atmosphere?
Combustion
Respiration
Greenhouse gases produced by natural sources are much less harmful than greenhouse gases produced by human activity.
False
The most important greenhouse gas on Earth is carbon ___.
dioxide
**carbon dioxide
Which of the following options correctly describe the greenhouse effect?
--- The greenhouse effect is a natural process
--- The greenhouse effect causes the average temperature on Earth to be higher than predicted when considering its distance from the sun.
--- Atmospheric gases on Earth trap about 80% of the infrared radiation produced by the Earth, warming the planet.
The most common strategies currently being developed to reduce levels of atmospheric CO>2 generally focus on ___.
technologies and fuels that produce less atmospheric CO>2
Which of the following can be attributed to the atmosphere of planet Earth?
The Earth's average temperature is higher than expected when considering its distance from the Sun.
Which of the following options correctly describe how aerosols interact with radiation and affect Earth's tmperature?
--- Aerosols promote cloud formation, allowing more solar radiation to be reflected. This has a cooling effect.
--- Aerosols scatter incoming radiation effiently, decreasing the amount of radiation available for greenhouse gases to absorb.
Any process that decreases the Earth's reflectivity causes the amount of radiation absorbed to ___ and temperatures to ___.
Increase
increase
Radiactive forcings ____.
--- may have either a cooling or heating effect on Earth
--- are gactors that influence the balance of incoming and outgoing radiation on earth
Any action undertaken with the purpose of permanently eliminating or reducing the long-term risks and haxards of climate change is called climate ____.
mitigation
** climate mitigation
Which of the following statements correctly describe the carbon cycle?
--- The main atmospheric form of carbon is CO>2
--- CO>2 is generated by the combustion of fossil fuels.
The organic material that decomposed to form fossil fuels has a very ___ level of carbon-14. Burning fossil fuels therefore causes a ___ in the concentration of carbon-14 in atmospheric CO>2.
Low
Decreases
Aerosols scatter incoming radiation very effectively, so that ____ IR radiation is absorbed and trapped by atmospheric greenhouse gases. This leads to a ___ effect.
less
cooling
Direct measurements of atmospheric CO>2 levels in Hawaii show that since 1960 ____.
--- The CO>2 levels in a given year fluctuate depending on the time of the year.
--- The annual average CO>2 levels have increased steadily.
The natural process by which Earth's atmospheric gases trap the infrared radiation radiated by Earth is called the ____ efect. This causes Earth's average surface temperature to be ____ than that predicted when considering the distance of the Earth from the Sun.
greenhouse
higher
What is the global atmospheric lifetime of a gas?
The time required for removal of a gas that has been added to the atmosphere
In order to be a greenhouse gas, a molecule must ___.
--- undergo a change in overall cxharge distribution during vibration
--- be composed of two or more different atoms
Which of the following will increase the Earth's albedo, causing a cooling effect?
--- Deforestation for the purpose of crop cultivation
--- An increase in snow or ice cover
Which of the following sources provide information about atmospheric CO>2 levels over time?
--- Direct atmospheric measurements
--- Data obtained from air bubbles trapped in ice cores
Both Venus and Earth have higher average surface temperatures than expected because ____.
both palnets have atmospheres that trap radiation.
Methane gas (CH>4) is produced when organic matter is decomposed by ___ bacteria, which are bacteria that function without the use of ___.
anaerobic
O>2
anaerobic bacteria
CH>4 (methane) has a global warming potential 20 times greater than that of CO>2. Why is CO>2 considered so much more important than CH>4 in any discussions about climate change?
--- CH>4 has a much shorter atmospheric lifetime than CO>2
--- The atmospheric concentration of CH>4 is much lower than the atmospheric concentration of CO>2.
The atomic mass of Magnesium is 24.31. Given the Avogadro's number is 6.02x 10^23, what is the average mass of one MG atom?
4.04x 10^-23 g

(divide atomic mass by size of collection)
Which of the following options correctly describe variations in solar irradiance and its effect on Earth's climate?
--- Seasonal variations in sunlight intensity affect local temperatures significantly.
--- Changes in the Earth's orbit can affect the amount of solar radiation that reaches the Earth.
How can ice-core data provide information about changes in atmospheric CO>2 levels over time?
Air bubbles trapped in the ice are analyzed to determine th CO>2 content at a particular time period.
Which of the following CANNOT act as a greenhouse gas?
H>2
Cl>2
An infrared spectrum records
intensity of transmitted radiation vs. wavelength
What is climate adaptation?
The ability of a system to adjust to climate change, in order to moderate potential damage
Influences on the environment resulting from human activities are called ___ influences.
anthropogenic
Which of the following is the greatest source of atmospheric N>2O, a gas that contributes to global warming?
Bacteria convert soil nitrates to N>2O.
Positive forcings from greenhouse gases are roughly ____ times ___ than those from solar irradiance.
30
greater
H>2O molecules containing the isotope ^2H condense ____ readily than H>2O molecules containing ^1H, causing snow and ice to be enriched in ____ when compared to ocean water. The ^2H/^1H ratio in ice depends on temperature, and this value can be measured and used to estimate the temperature at the time the ice formed.
more
^2H
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