CHEM 101 CHAPTER 3

Calculate the velocity of a wave with a frequency of 3.5 x 10-5 s-1 and wavelength of 5.1 x 108 m.

1.8 x 10^4 m/s

Which of the following statements correctly describe the origin and uses of CFCs? Select all that apply.

CFCs are very chemically persistent molecules. CFCs are inert and nontoxic.

Select the allotrope of oxygen whose bonds can be broken by UVB radiation.

O3

What characterizes a free radical?

One or more unpaired electrons

Which of the following options correctly describe how to draw a Lewis structure for a given molecule? Select all that apply.

The A-group number of a main-group element gives the number of valence electrons. Each line between two atoms represents two electrons. The Lewis structure includes only the valence electrons for the molecule.

Which of the following statements correctly describes the consequences of halting the production of CFCs?

There has been a slow decrease in the concentration of stratospheric chlorine since the halt in production of CFCs.

Rank the three types of UV radiation in order of increasing wavelength, starting with the shortest wavelength radiation at the top of the list.

UV-C UV-C UV-A

Which of the following options correctly describe the different types of UV radiation? Select all that apply.

UV-C radiation has the shortest wavelength. UV-A is the least damaging to the Earth's surface. UV radiation with a wavelength of 300 nm is classified as UV-B radiation.

Mineral-based sunblock preparations may contain _______. (Select all that apply.)

ZnO TiO2

The most significant step toward halting the depletion of the ozone layer was the call to stop the production of _____.

chlorofluorocarbons

Lewis structures are used to represent covalent compounds. Shared electron pairs are shown either as pairs of or lines and only electrons are shown.

dots; valence

E

energy per photon

The _____________ of a wave is the number of wave cycles per second.

frequency

According to the relationship E = hc/λ, energy and wavelength are _____ related. Therefore, the shorter the wavelength the _____ the energy of the radiation.

inversely; greater

The process by which green plants convert sunlight into stored chemical potential energy by producing glucose and oxygen is called ______.

photosynthesis

c

speed of light

Select the correct symbol for frequency.

v

Electrons that are found in the highest energy level are called ________________ electrons.

valence

λ

wavelength

The distance a wave travels during one cycle is called its _____________. This is usually measured as the distance between two ___________ or two troughs.

wavelength; peaks

How many valence electrons does Be have?

2

A boron (B) atom has _____________ valence electrons.

3

A single covalent bond is indicated by:

A single solid line

h

Planck's constant

Select the correct symbol and units for wavelength. More than one unit and/or symbol may be correct.

nm λ

How many valence electrons does C have?

4

Calculate the wavelength of a wave with velocity of 5.1 x 104 m/s and frequency of 1.1 x 108 s-1.

4.6 x 10-4 m

How many valence electrons does F have?

7

How many valence electrons does Ne have?

8

The octet rule states that when atoms bond they may lose, gain, or share electrons in order to attain an outer level containing ____________ electrons.

8

Atoms bond in order to fill their valence shell of electrons. Most elements strive for a total of _____ such electrons while hydrogen strives for a total of _____.

8; 2

Which of the following statements correctly describe a Lewis structure? Select all that apply.

Bonding electrons are shown as lines or pairs of dots between two atoms. Lone pairs are shown as pairs of dots on individual atoms.

During photosynthesis ________.

CO2 and H2O are consumed to produce stored glucose Sunlight is converted into stored chemical potential energy

Place the steps for drawing a Lewis structure in the correct order, starting with the first step at the top of the list.

Count the number of outer electrons contributed by each atom. Add the valence electrons contributed by each individual atom to determine the total number of outer electrons for the species. Arrange the outer electrons in pairs around the contributing atoms. Ensure that each atom has a full outer shell.

Which of the following statements correctly describe the general characteristics of a covalent bond? Select all that apply.

Electrons in a covalent bond are common property to both atoms that make up the bond. A covalent bond involves the attraction between the nucleus of each atom and the electrons of the other. A covalent bond involves the sharing of electrons between two atoms.

True or false: Once the production of CFCs was halted there was a dramatic decrease in the amount of stratospheric chlorine.

False

A catalyst ______. (Select all that apply.)

Is typically regenerated during the reaction. Undergoes no permanent change during a reaction

Which color of visible light will have the lowest energy photons?

Red

Draw the Lewis structure for the covalent molecule CCl4. Which of the following statements correctly describes the Lewis structure of CCl4? Select all that apply.

The Lewis structure of CCl4 contains four single bonds. The Lewis structure of CCl4 contains 12 lone pairs.

Which of the following is a common ingredient in mineral-based sunblock formulations?

TiO2

True or false: CFCs are inert, nontoxic compounds.

True

Which of the following regions of the electromagnetic spectrum have sufficient energy to break covalent bonds? (Select all that apply.)

Ultraviolet X-ray

Place the steps taken to reduce the depletion of the ozone layer in chronological order, starting with the first step at the top of the list.

United Nations Environmental Programme: World Plan of Action on the Ozone Layer Vienna Convention on the Protection of the Ozone Layer Montreal Protocol Complete stoppage of production of CFCs in developing nations

A substance that participates in a chemical reaction but is regenerated so that it undergoes no permanent change is called a(n) ______.

catalyst

The bond formed between two nonmetals is called a(n) _____ bond. This bond involves the _____ of one or more electron pairs between the two atoms.

covalent; sharing

Replacing halogen atoms (such as Cl) in CFCs with hydrogen results in a(n) _____. Select all that apply.

decrease in boiling point decrease in molar mass

A highly reactive species with one or more unpaired electrons is called a(n) _____.

free radical

The speed of a wave is determined by multiplying the _____________ of the wave by its wavelength. In a vacuum all electromagnetic radiation travels at a constant speed: ______________ m/s.

frequency; 3.00 x 10^8

Introducing too many Cl atoms into a potential replacement for CFCs causes a(n) _____ in flammability and a(n) _____ in boiling point.

increase; increase

Wavelength and frequency are _____ proportional to each other. As wavelength increases frequency will _____.

inversely; decrease