Exam 2 Study Guide

Which of the following statements correctly describe isotopes?

- Each element's atomic mass is weighted average of the masses of the elements' isotopes. - Isotopes have different numbers of neutrons.

Which of the following options correctly describe how to name an ionic compound?

- The cation is named first and the anion second - When naming the anionic portion of the ionic compound, the element name is changed to end in -ide

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.

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.

Which of following correctly interprets balanced equation CH4 + 2O2 -> CO2 + 2H2O?

1. 1 molecule of CH4 reacts with 2 molecules of O2 2. 15 mol of CH4 will produce 15 Mol of CO2 when burned completely in O2 3. 1 mole of CH4 produces 1 mole of CO2 when reacted with 2 moles of O2

Which of the following ion combinations will result in an ionic compound that has a balanced number of positive and negative charges?

1. 2Li+ and S2 2. Na+ and Br- 3. Ca2+ and 2F

Which of the following are considered possible effects of climate change?

1. An increase in the incidence of insect-borne diseases 2. Changes in freshwater distribution 3. Rise in sea levels

An atom may lose or gain electrons to form an ion. Match description of ions and charges.

1. An ion with more electrons than its neutral atom is called: anion 2. An ion with fewer electrons than its neutral atom is called: cation 3. Charge of an ion with more electrons than its neutral atom is: negative 4. Charge of an ion with fewer electrons than its neutral atom is: positive

Which of the following options correctly describe the enhanced greenhouse effect?

1. Atmospheric gases trap and return more than 80% of the heat radiated by Earth. 2. This effect has resulted in an increase in average global temperatures on earth.

Which of the following will increase the earths albedo causing a cooling effect?

1. Deforestation for the purposes of crop cultivation 2. An increase in snow or ice cover

Which of the following conclusions were reached by the IPCC?

1. Human activities play an important role in climate change. 2. The average global temperature of the Earth is increasing,. 3. The burning of fossil fuels has a major impact on climate change.

Which of the following statements correctly describe ions?

1. Ions are formed when atoms lose or gain electrons. 2. F is an example of an anion.

Rank the following countries in order of increasing ecological footprint. Lowest to highest.

1. Mexico 2. China 3. France 4. United States

Direct measurements of atmospheric CO2 levels in Hawaii show that since 1960 _____.

1. The annual average CO2 levels have increased steadily. 2. The COs levels in a given year fluctuate depending on the time of year.

Which of the following options correctly describe electronegativity and its trends?

1. The higher the electronegativity value of an element, the more strongly it attracts bonding electrons to itself. 2. Electronegativity increases from left to right in the periodic table. 3. The element with the highest electronegativity is fluorine.

Which of the following options describe the correct format used to represent a chemical compound?

1. The number of atoms/ions in the formula is indicated by a subscript 2. In the formula of an ionic compound the cation is always placed first

Which of the following options correctly describe the electron groups and geometry of the molecule shown?

1. There are 4 electron groups around the central P atom. 2. The molecule is trigonal pyramidal in shape

The periodic table lists the atomic mass of Nitrogen as 14.01. How is this value interpreted?

1. This value takes into account the masses and abundances of the isotopes of nitrogen. 2. This is the average mass of an atom of nitrogen.

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.) Determine the shape of the molecule by examining the position of the bonding and nonbonding electron pairs with respect to each other.

Calculate the mass of 2.50 × 104 molecules of nitrogen gas.

1.16 x 10(-18) g

Calculate the molar mass of CHFCl2. In your answer, use 1 decimal place.

102.9

The bond angle for a tetrahedral molecule is equal to ___.

109.5

This figure shows global emissions of C in metric tons per person per year for selected countries. Using this figure, how many metric tons of carbon dioxide are released per person in Germany per year?

11 (____ x 3.67)

The isotope Mg-25 isotope has ____ protons and ____ neutrons in its nucleus. Mg has an atomic number of 12.

12; 13

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

If the average temperature of earth is currently 15.0°C, what does the NOAA model (the line in the graph) predict for the average global temperature in 2080?

17.4C

One year, a herd of cattle released 9.7 metric tons of CH4 (methane) into the atmosphere. How many metric tons of carbon did this methane contain?

2.4 metric tons C

What is the mass of exactly 500 sulfur atoms?

2.66 x 10(-20) g

Determine the molar mass for fluoxetine (C16H16F3NO), also known as Prozac®.

295.3 g/mo

The CO2 molecule has a linear shape which is consisted with _____ electron groups around the central carbon atom. The four electrons of each double bond therefore count as _____ electron group.

2;1

Suppose you have an Avogadro's number of potassium atoms. How many grams does this represent? Enter your answer to one decimal place.

39.1

Find the molar mass of ethanol, C2H6O.

46.07 g/mol

Calculate the mass percent of chlorine in CCl3 F (Freon-11).

77.5 percent

Although coal is a complex mixture of substances, its elemental composition can be approximated by the formula C135H96O9NS. Using this chemical formula, calculate the percentage, by mass, of carbon (C) in coal.

85 percent

What is the mass of one atom of iron (Fe)? Report your answer to 2 significant figures.

9.27 x 10(-23) g

Which statement correctly describes the procedure used to predict the ion formed by a maingroup element?

A metal loses enough electrons to attain the same numberas its nearest noble gas.

Match each labeled bond in the wedge-dash representation shown to its correct meaning.

A: In the plane of the page B: In front of the plane of the page C: Behind the plane of the page

Which of the following options correctly describe how aerosols interact with radiation and affect Earth's temperature?

Aerosols promote cloud formation, allowing more solar radiation to be reflected. This has a cooling effect. Aerosols scatter incoming radiation efficiently, decreasing the amount of radiation available for greenhouse gases to absorb.

Ratio of electromagetic radiation reflected from a surface relative to the amount incident

Albedo

The proportion of incoming radiation that is reflected by a surface is called the _____.

Albedo

An ____ solution is one in which water is the solvent.

Aqueous

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; change

Which human activity has the greatest net effect on atmospheric CO2 levels?

Burning fossil fuels

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

Which of the following elements will form a cation?

Ca Rb

Which of the following formulas for ionic compounds are written correctly?

CaCO3, Mg3(PO4)2, NaNO3

Which of the following formulas for ionic compounds are correct?

CaO Ca3N2

One system used in the United States to encourage reduction in CO2 emissions is the ___ and ____ system, which sets an upper limit for CO2 emissions for the year for a given company.

Cap; trade

The most abundant isotope of ______ is the internationally accepted standard for determining atomic mass.

Carbon

Natural location that store carbon usually in the form of one of its compounds and that naturally exchange carbon with each other are known as _____.

Carbon reservoirs

Match each element with the appropiate charge in its ionic form.

Cl = -1 Sr = +2 S = -2 Al = +3

Which explanation accounts for the fact that, on average, cloudy nights are warmer than clear nights?

Clouds are composed of water vapor and H2O is a strong greenhouse gas

Radiative forcings are factors that influence the balance of the Earth's incoming and outgoing radiation. Order these selected examples from Cooling to Warming.

Cooling -> Warming Aerosols, Stratospheric Ozone, Methane & Carbon Dioxide Smoke, soot and sulfate aerosols from coal combustion -> Fresh snow in winter -> Increased sunspots -> Halocarbons in the atmosphere

The most important greenhouse gas on earth is carbon ____.

Dioxide

An estimate of the biologically productive space necessary to support a particular standard of living is called a(n) _____.

Ecological footprint

The ability of a covalently bonded atom to attract the shared electrons is called ______.

Electronegativity

The process by which atmospheric gases trap and return more than 80% of the heat energy radiated by Earth called the _____ greenhouse effect, resulting in an increase in average global temperatures.

Enhanced

Iron(III)Sulfate

Fe2(SO4)3

The most electronegative element is _____.

Fluorine

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

Fuels formed by natural processes such as the decomposition of prehistoric organisms are called _____ fuels.

Fossil

A gas that is able to absorb and trap infrared radiation resulting in a warming of the atmosphere, is called a _____ gas.

Greenhouse

The most abundant greenhouse gas in Earth's atmosphere is

H20 Vapor

Match each type of radiaation 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

Which of the following is NOT a likely consequence of increased carbon dioxide concentration in the atmosphere?

Increase in bioversity

Any gas that can absorb ____ radiation can act as a greenhouse gas.

Infrared

In order for a molecule to absorb IR radiation, which of the following must be true?

Its bond vibration must involve a change in charge distribution.

Which of the following has the greatest impact on global warming?

Levels of atmospheric greenhouse gases.

Nonbonding electron pairs are also referred to as ___ pairs.

Lone

One _____ of any substance contains Avogadro's number of particles.

Mole

The molar mass of any substance is the mass of 1 _____ of the particles of that substance.

Mole

Which atmospheric component does not contribute to global warming?

N2

Which of the following is NOT a greenhouse gas?

N2

Which greenhouse gases were specifically targeted by the Kyoto protocol?

N2O CO2 Hydrofluorocarbons

the chemistry of carbon-based compounds is called ____ chemistry.

Organic

The process whereby a solid forms and separates from solution is called _____.

Precipitation

Factors that influence the balance of earth's incoming and outgoing radiation are called _____.

Radiative forcings

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

Substance that dissolves into a solvent

Solute

A ______ is a homogeneous mixture that consists of a solvent and one or more solutes.

Solution

Which of the following are three-dimensional representations of a molecule?

Space-filling model Wedge-dash representation

Describe the shape of a CH4 molecule.

Tetrahedral

The molecule shown has a ____ shape.

Tetrahedral

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 a polyatomic ion?

The atoms of a polyatomic ion are held together by covalent bonds. The charge on a polyatomic ion belings to the whole unit.

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.

Which of the following correctly reflects Avogadro's number?

There are 6.02 x 10(23) atoms in 12g of carbon-12.

Which of the following options correctly describe the expected greenhouse gas activity of CH2Cl2?

This molecule can undergo bending vibrations that will absorb IR radiation This molecule will absorb IR radiation and can behave as a greenhouse gas

Determine the shape or geometry of PH3. (Hint: Use the Periodic Table to arrive at the electron configuration for phosphorous.)

Trigonal pyramidal

Carbon reservoirs ______.

Usually contain carbon in the form of one of its compounds. Isolate carbon from the carbon cycle. Exchange forms of carbon with each other.

Gas most important to maintaining temperature of

Water

Describes daily high and low temperatures, rain, blizzards, etc.

Weather

The greenhouse effect refers to the process by which

atmospheric gases trap and return infrared radiation radiated by Earth.

Isotopes are atoms of the same element that have the same_________ number but a different ___________ number. This is because isotopes have the same number of protons but a different number of _________.

atomic; mass; neutrons

Match each type of electron pair to the correct designation.

b - bonding electron pair a - lone pair

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

In a(n) _____ compound electrons are transferred from one atom or group of atoms to another. Conversely, in a(n) _____ compound electrons are shared.

ionic; covalent

What is the correct systematic name for the ionic compound Li3N?

lithium(III) nitride

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

What is the correct systematic name for the compound Na2CO3?

sodium carbonate

The most abundant component of a solution is usually called the ___, whereas the other dissolved components are called___.

solvent; solute

Match each molecular shape correctly to its associated bond angle.

tetrahedral- 109.5 trigonal planar- 120 linear- 180 trigonal pyramidal- less than 109.5

Degasification is _____.

the loss of a gas from a liquid solution.

Organic Chemistry is ____.

the study and production of carbon-containing compounds

The internationally accepted atomic mass standard is carbon-12 because this isotope

was arbitrarily selected as a convenient standard.