Chem- chapter 3
space-filling models of ozone molecules
(all red)
which of the following statements correctly describe the origin and use of CFCs?
*CFCs are very chemically persistent molecules *CFCs are inert and nontoxic
which of the following statements correctly describes a Lewis Structure?
*Lone pairs are shown as pairs of dots on individual atoms *bonding electrons are shown as lines or pairs of dots between two atoms
draw the lewis structure for the covalent molecule CCL4. Which is the following statement correctly describes the lewis structre of CCl4?
*The lewis stru cture of CCL4 contains 4 single bonds *the lewis stuctre of CCl4 contains 12 lone pairs
which of the following statements correctly describe the general characteristics of a covalent bond?
*a covalent bond involves the attraction between the nucleus of each atom and the electron of the other *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
which of the following statements correctly describe resonance forms?
*an individual resonance form does not accurately represent the structure of the species *no individual resonance form actually exist *resonance forms differ only in the arrangement of electrons
which of the following options correctly describe how to draw a Lewis structure for a given molecule?
*each line between two atoms represents two electrons *the A-group number of a main-group element gives the number of valence electrons *the Lewis structure includes only the valence electrons for the molecule
which of the following statements correctly describe a photon?
*matter cannot absorb or emit a fraction of a photon *a photon is a particle of electromagnetic radiation
which of the following statements correctly describe the formation of ozone?
*ozone can be formed from O2 *Ozone is typically formed during a lightning storm
which of the following statements correctly describe natural variation in stratospheric ozone level?
*random fluctuation in ozone concentration occur *the amount of radiation emitted by the sun varies over an 11- to 12- year cycle, which causes variation in ozone production
during photosynthesis
*sunlight is converted into stored chemical potential energy *CO2 and H2O are consumed to produce stored glucose
which of the following option correctly describe the unique conditions in the antarctic that cause the region to have disproportionately large hole in the ozone layer
*temps are cold as -90c *polar stratospheric clouds formed in this region initiate reactions of benign species to more reactive species *winds in the area form a vortex that prevents warmer air from entering the Antarctic
a catalyst (select all that apply)
*undergoes no permanent change during a reaction *is typical regenerated during the reaciton
although HFCs are a good replacement for CFCs in terms of their physical properties and effect on the ozone layer, these compounds_______
-are green house gases -play a role in global warming
match the following types of radiation with the correct region of the electromagnetic spectrum
0.005nm- gamma ray 400nm- visible 50um- IR 150mm- microwave
place the reaction steps in order for the reaction of CFCs with stratospheric ozone, starting with the first step at the top of the list
1. CFC is bombarded with UV light releasing a chlorine radical 2. chlorine radicals react with ozone to produce CIO and oxygen 3. two CIO radicals combine to form CIOOCI 4. CIOOCI decomposed under UV radiation to CIOO and chlorine radial 5. CIOO decomposes to a chlorine radical and oxygen
place the steps for drawing 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 to determine the total number of outer electrons for the species 3. arrange the outer electrons in pairs around the contributing atom 4. ensure that each atom has a full outer shell
arrange the following types of radiation in order of increasing energy per photon starting with lowest energy at the top of the list
1. radio waves 2. infrared radiation 3. visible light 4. gamma rays
rank the following types of bonds from the longest to the shortest, starting with longest bond at the top of the list
1. single covalent 2. double covalent 3. triple covalent
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 nation environmental programme 2. Vienna convention on the protection of the ozone layer 3. Montreal protocol 4. complete stoppage of production of CFCs in developing nation
the distance a wave travels during one cycle is called its _______. this is usually measured as the distance between two ____ or two troughs
1. wavelengths 2. peaks
place the following type of electromagnetic radiation in order of increasing wavelength (shortest at the top and longest at the bottom)
1. x-ray 2. UV radiation 3. visible light 4. IR radiation 5. radiowaves
rank the three of UV radiation in order of increaing wavelength, starting with the shortest wavelength radiation at the top
1.UVC 2.UVB 3.UVA
the danger of sunburn is greatest with the UV index is equal to ________
15
a boron (B) atom has _____ valence electrons
3
Speed of light in air or a vacuum c=
3.0 x 10^8 m/s
Speed of light in air
3.00 x 10^8 m/s
speed of light in a vacuum
3.00 x 10^8 m/s
the covalently bonded species shown has _____ shared pair(s) of electrons and ______ lone pair(s)
3; 1
frequency of green light with wavelength of 525nm
525 nm x 1x10^-9 m/1nm =5.25 10^-7 m; 3.00x10^8 m * s^-1/ 5.25 *10^-7 m =5.71 * 10^14 ^-1 =5.71* 10^14 Hz
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
exact value for speed of light in air vs vacuum
870 um/s slowerer 2.99705x10^8m/s vs. 2.99792 x 10^8 m/s
atoms bond in order to fill their valences 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 option is the correct Lewis Structure for the molecule N2
:N=(three lines)N:
double bond
A covalent bond in which two pairs of electrons are shared between two atoms
which coefficients are needed to balance the simplified chemical equation representing the formation of the ozone? energy + a O2> bO3 A=_______ and b=________
A=3 B=2
match each elements with the correct number of valences electrons
C-4 Be-2 Ne-8 F-7
CFCs always contain _______
Chlorine carbon fluorine
Resonance forms are correctly defined as_______
Lewis structures for the same species that differ in the placement of electrons
resonance forms
Lewis structures that represent hypothetical extremes of electrons arrangement in a molecule
match each form of oxygen with the wavelength of UV radiation that is sufficient to break its bond
O3- <320 O2- <242
ROY G BIV
Red, Orange, Yellow, Green, Blue, Indigo, Violet
frequency
The number of complete waves that pass a given point in 1 second
single covalent bond
a bond formed when two atoms share a pair of electrons
steady state
a condition in which a dynamic system is in balance so that there is no net change in concentration of the major species involved
triple bond
a covalent linkage made up of three pairs of shared electrons
structural formula
a representation of how the atoms in molecule are connected. it is a Lewis structure from which the non-bonding electrons have been removed
scientific notation
a system for writing numbers as the product of a number and 10 raised to the appropriate power
quantized
an energy distribution that is not continuous, but rather consists of many individual steps
resonance forms are Lewis structures that have the same relative placement of _______ but a different arrangement of _______
atoms; electrons
Why do you think exposure to the sun can cause damage
being out in the sun too long causes painful burns and blisters on the surface of the skin. damage is also occurred under the skin that we cannot see. the UV light has shorter wavelengths than visible or IR rays. our skin and eyes are sensitive to those photons and can become damaged by this form of light energy.
exposure category very high
carful if you are outside on sand, snow, or water as the surfaces relect UV, increasing your exposure. min exposure between 10a-4p index 8-10
a substance that participates in a chemical reaction but is regenerated so that it undergoes no permanent change is called a(n)_____
catalyst
match each type of formula with the correct description
chemical formula: shows only types and ratios of atoms present structural formula: representation of how atoms are arranged, omitting lone pairs of electrons Lewis structure: representation of how atoms are connected, including lone pairs electrons
catalyst
chemical substance that participates in a chemical reaction and influence its rate, without itself undergoing permanent change
Chlorofluorocarbons (CFCs)
compounds composed of the elements chlorine, fluorine, and carbon (but do not contain the element hydrogen)
hydro
compounds contain C-H bonds
fluoro
compounds that contain C-F bonds
olefin
compounds that contain C=C double bonds
photons
conceptualizing light as a particle that has energy but no mass
electromagnetic (EM) spectrum
continuum of waves that range from short, high-energy X-Rays and gamma rays to long, low- energy radio waves
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
exposure category high
cover up, wear a hat and sunglasses and use sunscreen. reduce exposure between 10a-4p index 6-7
wavelengths
distance between successive peaks in a sequence of waves
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
valence electrons
electrons in the outermost shell
radiation
emission of energy as electromagnetic waves or as moving subatomic particles
what is emitted from the sun?
energy from ultraviolet, infrared and visible light radiation
Resonance forms are different possible structures for the same species that interconvert rapidly
false
a highly reactive species with one or more unpaired electrons is called
free radical
the ________ of a wave is the number of waves cycles per second
frequency
the speed of wave is determined by multiplying the _________ of the wave by its wavelength. in a vacuum all electromagnetic radiation travels at a constant speed, the speed of ________
frequency; light
octet rule
generalization that electrons are arranged around atoms so that these atoms have a share in eight electrons. hydrogen is an expection
for the main-group elements (1, 2, ect.) the number of valences electrons for an element is equal to the _______ number for the element
group
energy and wavelength are related throuh the equation e=hc/n. match each symbol with the correct identity
h- planck's constant c- speed of light e- energy per photon n- wavelength
shorter wave
higher frequency
what is the maximum number of ozone molecules per billion molecules and atoms of all types found in the stratosphere
highest concentration of ozone in the stratosphere is 12,000 ozone molecules per billion molecules and atoms of all types, which is 12,000ppb
free radicals
highly reactive chemical species with one or more unpaired electrons
match each prefix or term to its correct meaning when applied to an organic compound
hydro: C-H fluoro: C-F olefin C=C
exposure category low
if you burn easily, cover up and use sun screen index:0-2
what is the maximum number of ozone molecules per billion molecules and atom of all types found in ambient air just meeting the EPA limit for an 8hr average
in ambient air, ozone levels can be between 20 and 100 ppb or more. the EPA suggest limiting your ozone exposure to 75 ppb in 8hr period
Halons
inert, nontoxic compounds that contain chlorine or fluorine (or both, but no hydrogen). But in addition, they contain bromine
wavelength and frequency are _____ proportional to each other. as wavelength increase frequency will ____
inversely; decrease
according to the relationship E=hc/n, energy and wavelength are ______ related. therefore, the shorter the wavelength the _______ the energy of the radiation
inversely; greater
twofold nature of radiation
know as wave-particle duality
what kind of damage can the sun cause
lasting effects of sundamge are evidenced by wrinkled, leathery skin, and the presence of solar lentigines (sun spots) on the skin. cataracts and other eye problems can develop form prolonged UV exposure
longer wavelengths
lower frequency
a species such as Cl2 or H2O, in which the atoms are connected by shared electron pairs, is called a(n)
molecule
select the correct symbol and units for wavelength. more than one unit and or symbol may be correct
nm, and upside down V
designated region in the stratosphere of maximum O3 concentration is called ____ layer
ozone
electromagnetic radiation consists of particles called _______, 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 specific ______ and frequency
photons; wavelength
what type of clouds are composed of tiny icy crystals formed from a small amount of water vapor present in a specific region of the atmosphere?
polar stratospheric clouds
energy is not continuous, but is ___________, which means that it is divided into "packets" each of which contains a definite amount of energy
quantized
how many times longer is a wavelength associated with radio wave than one associated with an x-ray
radio wave is on the order of 10^1 m, while a x-ray is on the order of 10^-10m. this is a difference of 12 ordered of magnitude, which means x-rays are 10^12 times as energetic as a radio waves
Frequency (v)=
speed of light (c)/ wavelength ()
exposure category moderate
stay in the shade when the rays of the sun are strongest index:3-5
exposure category extreme
take full precaution against sunburn. unprotected skin can burn in minutes. avoid the sun 10a-4p index 11+
what is the approximate altitude of maximum ozone concentration
the approximate of maximum ozone concentration is 23 km(14 miles) above sea level
Which type of electromagnetic radiation comprises the greatest portion of the energy from the sun
the greatest portion of energy from the sun reaches earth as infrared radiation
Photosynthesis
the process by which green plants and some other bacteria capture the energy of sunlight to produce glucose and oxygen from carbon dioxide and water
energy is quantized. what
there is a basic unit of energy that cannot be subdivided further
polar stratospheric clouds (PSCs)
thin clouds composed of tiny ice crystals formed from the small amount of water vapor present in the stratosphere
lone pairs
three pairs of electrons are not shared with other atoms; as such, they are called non-bonding electrons
match each region of the atmosphere correctly with the abundance of ozone
troposphere- 100 O3 (upper limit) per billion molecules that make up the air stratosphere - 12,000 O3 molecules (upper limit) per billion molecules that make up the air
the region of the atmosphere closest to earth is called the ______. the region of the atmosphere that contains the ozone layer is called the ______
troposphere; stratosphere
four types of radiant energy from the electromagnetic septum. arrange in order
ultraviolet radiation < visible radiation < infrared radiation < microwave radiation
which type of radiation is the most intense
visible light with a wavelength around 500nm
what are some positve effects of the sun
vitamin D production
UVC
wavelength: 200-280 nm relative energy: highest although UVC radiation is very harmful, it is completely absorbed by O2 and O3 in the stratosphere
UVB
wavelength: 280-320nm relative energy: medium most UVB is absorbed by Ozone in the stratosphere. UVB damages the outermost layer of the skin
UVA
wavelength: 320-400nm relative energy: lowest reaches earths surface in the greatest quantity and penetrates farthest into the skin