CHM: Chapter 3

which of the following statements correctly describes the general characteristics of a covalent bond?

- a covalent bond involves the sharing of electrons between two atoms - 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

Place the reaction steps in order for the reaction of CFC's with stratospheric ozone, starting with the first step at the top of the list

1. CFC is bombarded with UV light 2. Chlorine radicals react with ozone 3. two CIO radicals combine to form CIOOCI 4. CIOOCI decomposes under UV radiation 5. CIOO decomposes to a chlorine radical and oxygen

Which of the following statements correctly describe the origin and uses of CFC's

1. CFCs are intert and nontoxic 2. CFCs are very chemically persisted molecules

Which of the following statements describe the advantages and disadvantages of the replacements for CFC's

1. HFCs are nontoxic and nonflammable 2. HFCs are considered greenhouse gases

Which of the following statements correctly describe polar stratospheric clouds

1. PSCs provide a surface for chemical reactions to occur 2. psc are composed of tiny ice crystals

Which of the following options correctly describes how to draw a lewis structure for a given molecule?

1. The lewis structure includes only the valence electrons for the molecule 2. each line between two atoms represents two electrons 3. the A group number of a main group element gives the number of valence electrons

Draw the Lewis structure for the covalent molecule CCI4. Which of the following statements correctly describes the Lewis structure of CCI4?

1. The lewis structure of CCI4 contains four single bonds 2. the lewis structure of CCI4 contains 12 lone pairs

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

1. UV-C 2. UV-B 3. UV-A

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

1. United nations environmental programme 2. Vienna convention on the protection of the ozone layer 3. montreal protocol 4. complete stoppage of production of CFC's in developing nations

Which of the following statements correctly describes the general characteristics of a covalent bond?

1. a covalent bond involves the attraction between the nucleus of each atom and the electrons of the other 2. electrons in a covalent bond are common property to both atoms that make up a bond 3. a covalent bond involves the sharing of electrons between two atoms

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

1. count the number of outer electrons contributed by each atom 2. add the valence electrons contributed by each individual atom 3. arrange the outer electrons in pairs around the contributing atoms 4. ensure that each atom has a full outer shell

Which of the following statements correctly describes a Lewis structure?

1. lone pairs are shown as pairs of dots on individual atoms 2. bonding electrons are shown as lines or pairs of dots between two atoms

Rank the following types of radiant energy in order of increasing frequency.

1. microwave 2. infrared 3. visible 4. ultraviolet

Arrange the following types of radiation in order of increasing energy per photon, starting with the lowest energy radiation at the top of the list

1. radio waves 2. infrared radiation 3. visible light 4. gamma waves

Which of the following statements correctly describes natural variations in stratospheric ozone levels?

1. random fluctuations in ozone concentrations occur 2. The amount of radiation emitted by the sun varies over an 11 to 12 year cycle

Rank the following types of bonds from the longest to shortest, starting with the longest bond at the top of the list

1. single 2. double 3. triple

Which of the following factors cause an increase in ozone production

1. sun closer to the earth 2. increased intensity of UV radiation 3. increased intensity of UV radiation

a catalyst what?

1. undergoes no permanent change during a reaction 2. is typically regenerated during the reaction

Place the following types of electromagnetic radiation in order of increasing wavelength

1. xray 2. UV radiation 3. visible light 4. IR radiation 5. radiowaves

1 nm =

10 -9 m

Match each region of the atmosphere correctly with the abundance of ozone

100 O3 - troposphere 12,000 03 - stratosphere

The covalently bonded species shown has what shared pairs of electrons and what lone pairs

3:1

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

8

Match each type of formula with the correct representation

A - lewis structure B- structural formula c- chemical formula

Which of the following is the correct Lewis structure for the molecule OF2

B

Match each element with the correct number of valence electrons

C - 4 Be- 2 Ne- 8 F- 7

Match each molecule with the correct description of its bonding

H2O2 = the molecule posses no multiple bonds HCN= this molecule possesses one triple bond CS2= this molecule possesses two double bonds

Match each form of oxygen with the wavelength of UV radiation that is sufficient to break its bonds

Ozone = 320 Oxygen = 242

Match the molecular formula for each form of oxygen with the correct chemical name

Ozone = O3 Oxygen = 02

Match each type of radiation correctly with either its source or its function

UV radiation = given off by the sun Xrays = used in medical diagnosis Gamma rays = given off in nuclear decay Microwaves = used to cook food quickly

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

Y & nm

Which coefficients are needed to balance the simplified chemical equation representing the formation of ozone? a O2 = B O3

a = 3 and b = 2

resonance forms are lewis structures that have the same relative placement of what but a different arrangement of what

atoms & electrons

Which of the following options is the correct lewis structure for the molecule N2?

c

A substance that participates in a chemical reaction but is regenerated so that it undergoes no permanent change is called a

catalyst

In the destruction of ozone by CFCs chlorine is both consumed and regenerated during the cycle, with no net change in its concentration. Chlorine therefore acts as a what in the process

catalyst

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

dots & outer

A highly reactive species with one or more unpaired electrons is called a

free radical

The what of a wave is the number of wave cycles per second

frequency

The speed of a wave is determined by multiplying the what of the wave by its wavelength. In a vacuum all electromagnetic radiation travels at a constant speed, the speed of what?

frequency & light

For the main group elements the number of valence electrons for an element is equal to the what number for the element

group

Energy and wavelength are related through the equation E=hc/y. Match each symbol with the correct identity

h = Planck's constant c = speed of light E = energy per photon Y = wavelength

Match each prefix or term to its correct meaning when applied to an organic compound

hydro=bonds are present fluoro= C-F bonds are present olefin= C=C double bonds are present

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

inversely & greater

On average, the concentration of stratospheric ozone at the equator is what than at the poles

lower

A species such as CI2 or H2O, in which the atoms are connected by shared electron pairs, is called a what

molecule

What is the correct term used to describe the species HF, in which electrons are shared between H and F

molecule

A designated region in the stratosphere of maximum 03 concentration is called the what layer

ozone

Electromagnetic radiation consists of particles called what, each of which has a discrete amount, or quantum, of energy. However since electromagnetic radiation also has wave properties, each particle is also characterized by a specific what and frequency

photons & wavelength

Energy is not continuous, but is what, which means that it is divided into packets each of which contains a definite amount of energy

quantized

The energy associated with each of the different wavelengths in the electromagnetic spectrum is called what energy

radiant

Which color visible light will have the lowest energy photons

red

Energy is quantized. What does this mean?

there is a basic unit of energy that cannot be subdivided further

True or false: CFC's are inert, nontoxic compounds

true

Select the correct symbol for frequency

v

electrons that are found in the highest energy level are called what or outer electrons

valence