Chem quizzes and tests
Place the events of the history of ozone depletion in chronological order.
-1930s- Chlorofluorocarbons (CFCs) are invented and used as propellants and refrigerants by people worldwide. -1974-F. Sherwood Rowland, Mario Molina and Paul Cruzen discover that CFCs are a major cause of stratospheric ozone depletion. -1977-The United Nations meets and adopts the World Plan of Action on the Ozone Layer. -1978-The US and Canada ban the use of CFCs in spray cans. -1987-The Montreal Protocol on Substances That Deplete the Ozone Layer is signed and ratified by countries worldwide. -1990- present-Production and use of CFCs and other ozone depleting agents dramatically decreases.
in these diagrams, different atoms are represented by different colors. classify each sample according to the labels below
-Pure element- 1. (the 5 sets of green figure 8's) 2. (the 5 sets of all blue groups of 3) 3. (the 8 single purple dots) -pure compound- 1. (the purple and orange; 2 dots. each with one purple and one orange). 2. (the triple set with 2 blue and one yellow each) -mixture of an element and a compound- 1. (sets containing 2 dots each. some sets are 2 purple, some are 1 purple and one yellow -mixture of 2 elements-1. (orange and green single dots) 2. (5 sets of dots. sets contain 2 dots. 2 yellow dot sets, 3 purple dot sets -mixture of 2 compounds- 1. (2 dot sets, green/purple & yellow/ blue) 2. (5 triple sets, some 2 green/1 orange and some 2 orange/ 1 green)
the warming of a car in the sun is an excellent analogy for the greenhouse effect of our atmosphere. complete the analogy with the words and phrases then place the sentences in order.
-When sunlight hits a car, its windows absorb some radiation, such as UV-B. In the atmosphere, all of the UV-C and some of the UV-B radiation is absorbed by reactions of oxygen and ozone in the stratosphere. -The car windows allow visible light and infrared radiation to pass into the car. Similarly, our atmosphere allows higher energy infrared radiation and visible light to pass through. -The car's interior, like the Earth's rocks and soil, absorbs visible light and higher energy infrared radiation then emits lower energy infrared radiation back out. -The car windows, like the greenhouse gases of our atmosphere, trap the lower energy infrared radiation and makes the interior warmer than the outside.
which of these are correct? -All of these are correct -there is a dynamic steady state of ozone in the stratosphere -UV radiation will dissociate ozone into an oxygen atom and an oxygen molecule -ozone forms by combining an oxygen atom with an oxygen molecule
-all of these choices are correct
vibrations of some molecules will absorb infrared radiation while others will not. Do the following vibrations absorb?
-nitrogen: no -dichlorodifluoro-methane: yes -carbon dioxie: no
Give the number of protons, neutrons, and electrons in a neutral atom represented by 69Ga31 .
-protons: 31 -neutrons: 38 -electrons:31
predict the molecular shape for each of these compounds. remember to consider all of the outer electrons before you make your choice.
-tetrahedral: methane -Trigonal pyramidal: ammonia -trigonal planar: sulfur trioxide -bent: water; ozone
which one is the lewis structures for ozone (view answer in half screen)
.. .. .. O : : O : O : .. ..
Write 3.26 × 10−2 g as a "regular" number; that is, without scientific notation.
.0326
label the diagram below with the different types of electromagnetic radiation in the EM spectrum
1. Gamma rays (10^-12) 2. X-rays (10^-9) 3. Ultraviolet (UV) (10^-8) 4. Visible (10^-7) 5. Infrared (IR) (10^-5) 6. Microwave (10^-2) 7. Radio (10^1.5)
ozone is a dangerous secondary pollutant in our atmosphere. fill in the blanks and then rearrange the sentences to describe the formation of ozone
1. Nitrogen monoxide is produced when nitrogen & oxygen are exposed to high heat. 2.At high concentrations, nitrogen monoxide will directly react with oxygen to produce nitrogen dioxide, but in the atmosphere, its production is more complex. 3. One complex pathway to nitrogen dioxide requires the presence of VOCs and ·OH (a free radical). 4. The energy from sunlight splits the nitrogen dioxide to oxygen and nitrogen monoxide. 5. The free oxygen atoms in turn react with oxygen to form ozone.
Express 105 m in terms of nm.
1.05; 11 (1.05x10^11 nm)
How many atoms are contained in 3.1 g of carbon? Round your answer to 2 significant figures.
1.6 x 10^23 atoms
there are approximately 2x10^22 molecules and atoms in each breath we take and the concentration of CO in the air is approximately 9 parts per million. approximately how many CO molecules are in each breath we take?
1.8 x 10^17
To burn 1 molecule of C7H16 to form CO2 and H2O (complete combustion), how many molecules of O2 are required?
11 molecules
To draw a Lewis structure, first add the number of outer (valence) electrons contributed by each atom to obtain the total number of outer electrons. What is this value for a molecule of H2CCH2?
12 total valence electrons
this is the lewis structure for acetic acid. the bond angles are not drawn to scale. Based on the electronic configuration shown in the lewis structure, predict the O-C-O bond angle, in degrees
120 degrees
balance this equation P4+Cl2-->PCl5 with the smallest whole number coefficients. choose the answer that is the sum of the coefficients.
15
assuming that the burette was originally filled to the "0 mL" line at the top, what volume of liquid has been added to the titration at this point in the experiment?(3 marks above the 20 mL line)
17.0 mL
To draw a Lewis structure, first add the number of outer (valence) electrons contributed by each atom to obtain the total number of outer electrons. What is this value for a molecule of SO2?
18 outer electrons
Provide the proper coefficients (including 1's) required to balance this reaction:
1;3;2 (1N2+3H2-->2NH3
What is the mass of one atom of carbon (C)? Report your answer to 2 significant figures.
2.0 × 10^-23g
Calculate the volume of air in liters that you might inhale (and exhale) in 1.0 hour. Assume that each breath has a volume of 0.31 liters, and that you are breathing 11 times a minute.
204.6
a sample of silicon rejected for use in an electronic circuit has an impurity of boron at a level of 3 parts per trillion. what is the fraction of boron atoms in the silicon sample as written in scientific notation
3 X 10^-12
WUKF FM transmits at 93.5 MHz. What is the wavelength of the electromagnetic radiation that carries the station's signal?
3.21 m
Nail polish remover containing acetone was spilled in a room 6.6 m × 5.2 m × 2.9 m.Measurements indicated that 3,600 mg of acetone evaporated. Calculate the acetone concentration in micrograms per cubic meter. --X 10^-- μg/m3 (Enter your answer in scientific notation.)
3.6X10^4μg/m3
what is the answer to the following mathematical operation? 1.42+10.3x 2.854
30.8
choose the best reading of the volume of the liquid contained in the beaker and the temperature measured by the thermometer. make sure your answers have a reasonable number of decimal points.
41 mL; 57.0 degree C
Calculate the molar mass of N2O. In your answer, use 1 decimal place.
44.0 g/mol
Give the number of outer (valence) electrons for an atom of phosphorus.
5 outer electrons
different ways of expressing concentrations work best for different things. concentrations of pollutants are often expressed in parts per million because they are very small, even though their effects can be large. convert the parts per million values into percentages
5-0.0005% 50- 0.005% 500-0.05% 5000-0.5% 50000-5%
The quantity 0.0000064 g expressed in scientific notation
6.4 X 10^-6 g
One year, a herd of cattle released 8.6 metric tons of CH4 (methane) into the atmosphere. How many metric tons of carbon did this methane contain?
6.5 metric tons C
A sample of cigarette smoke contains 2.33% carbon monoxide. The U.S. national ambient air quality standard for CO in a 1−hr period is 35 ppm. How many times greater than this standard is the CO concentration in cigarette smoke?
666
how many carbon atoms does the molecule octane have?
8
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
A certain combustion reaction generates 2.0 moles of carbon dioxide. How many grams does this represent? Report your number to one decimal place.
88.0 g
Express this concentration in terms of ppm: 0.0009%
9 ppm
which of these represents the best lewis structure for acetylene (C2H2)?
A: H-C=(three lines)C-H
which of the following is the chemical symbol for silver?
Ag
The ozone hole is most prominent on the earth over
Antarctica
HFCs may be used to replace CFCs. Which compound is a HFC?
CF3CH2F
which component of air makes up approximately 100 times more of an exhaled breath than of an inhaled breath
CO2
although carbon dioxide is the primary compound discussed with respect to global warming; of the common atmospheric components the global warming potential (GWP) of a carbon dioxide molecule is very low. Which statement best explains this pair of facts?
CO2 exists in relatively high concentrations
Which lewis structure for formaldehyde (CH2O) is correct
D H. . .. C : : O . . H
categorize each compound as an HFC, CFC, HCFC or Halon (view answer in half screen)
HFC F H | | F- C - C - F | | F F H | F- C - H | F __________________ Halon F | Br- C- F | F _______________ CFC Cl | Cl-C-Cl | F Cl | F - C- Cl | F _______________ HCFC H | F - C - Cl | F Cl H | | F - C - C- H | | Cl H
categorize each compound as an HFC, CFC, HCFC or Halon
HFC- F F | | H-C - C -F | | F F H | F - C- H | F Halon- F | Br - C - F | F CFC- Cl | Cl - C - F | Cl Cl | Cl - C - F | F HCFC Cl | H- C - F | F H Cl | | H - C - C- F | | H Cl
why are HFCs environmentally superior to the currently used HCFCs?
HFCs do not contain chlorine
which of the following compounds is useful for putting out fires and does not deplete stratospheric ozone concentrations
Halon-1211
which diagram(s) represent(s) only molecules?
I and II only (I -the one with 4 molecules joined) (II- the one where 2 exact molecules are joined)
which square(s) contain(s) only one or more compounds
I only ( both compound pictured are exactly alike and has a dark center molecule with 2 light molecules attached. )
which diagram(s) best represent(s) only individual atoms
III only (single identical dots)
what international agreement attempted to reduce greenhouse gas emissions?
Kyoto protocol
which of the following compounds is considered to be an ionic compound
LiF
what is the primary component of exhaled breath?
N2
which substance is an element?
N2
which substance is not considered to be an air pollutant
N2
which is the balanced chemical equation for the reaction of nitrogen (N2) with oxygen (O2) to form NO?
N2+O2-->2NO
the chemical formula for nitrogen monoxide is
NO
which component of the air is an element
O2
which correctly pairs and indoor pollutant with its source?
O3 and electrical arching
which shows the balanced equation for the reaction of nitrogen (dark O), as it is normally found in our atmosphere , with oxygen (white O), as it is normally found in our atmosphere, to form nitrogen dioxide?
OO(dark, nitrogen)+OO(white, oxygen+OO(white oxygen)--> O(white, oxygen)O(dark, nitrogen)O(white, oxygen) + O(white, oxygen)O(dark, nitrogen)O(white, Oxygen
molecules and electromagnetic radiation interact. Atoms may dissociate, a molecule may rotate, or bonds may stretch and bend. Carbon dioxide has four possible vibrations. Select the true statements about the vibrations below.
Red molecule--><--Black molecule%% Red molecule--> -this vibration will change the charge distribution around the molecule. -this motion is called a stretching vibration -this vibration requires more energy -this vibration directly absorbs infrared radiation. Red molecule ^ Black molecule v Red molecule ^ -this vibration will change the charge distribution around the molecule -this motion is called a bending vibration - this vibration requires less energy -this vibration directly absorbs infrared radiation
how do mineral nanoparticles in sunscreens protect from UV radiation?
The particles absorb incoming UV light
which of the following is most biologically damaging type of radiation?
UV-C
which symbols represent only elements that are metals?
X and Z ( the left side of the table)
which one of the following is an example of a homogeneous mixture?
a glass of pulp free lemonade
which color in the rainbow has the shortest wavelength?
blue
light behaves like
both a particle and a wave
Which element is oxidized in this chemical reaction? 2Ca(s) + O2(g) →2CaO(s)
calcium
Give the number of carbon atoms, hydrogen atoms, and fluorine atoms in a molecule of HFC−32.
carbon atoms: 1 Hydrogen atoms: 2 fluorine atoms:2
in general, which airborne material is not likely affected by the filters or indoor handling equipment?
carbon monoxide
which country is the world's leading producer of rare earth elements?
china
which product of the ultraviolet decomposition of CFCs acts as the catalyst for ozone decomposition?
chlorine atoms
what type of material is defined as having a well- ordered atomic structure?
crystalline
wavelength is the
distance between successive peaks in a wave
which process plays the most important role in the greenhouse effect?
energy radiated by the earth is absorbed by the atmosphere
the "ozone layer" is found
in the stratosphere
land use changes have a big impact on global warming because of their effects on albedo. Albedo
is the ratio of electromagnetic radiation reflected by a surface to the amount of radiation hitting that surface.
Describe the shape of a CO2 molecule.
linear
use the chart below to relate the terms on the right.
matter | | pure substances mixtures | | elements compounds
the most numerous of the elements of the elements are the
metals
based on its name which carbon compound contains the fewest carbon atoms
methane
Classify the following compound as either molecular or ionic: XeF4
molecular
Give the name and chemical symbol for the element with 33 protons.
name: arsenic symbol: As
the burning of coal produces sulfur dioxide, SO2, a pollutant that slowly reacts in air to form SO3. sulfur trioxide dissolves into airborne water droplets to form a very corrosive solution of sulfuric acid. which is a product of burning coal that hastens the transformation of sulfur dioxide into sulfur tiroxide.
particles of ash
this illustration of an simplified atom highlights the three key subatomic particles. label each of them. assume the red particles are positively charged while the blue particles are neutrally charged
proton (on the left, inside cluster, red) electron-(top right, outside the cluster) neutron-(bottom right, inside cluster,blue)
which of the following is a subatomic particle located in the center of the atom and has a positive charge?
protons
Using the periodic table as a guide, specify the number of protons and electrons in a neutral atom of krypton(Kr).
protons-36 electrons-36
the intergovernmental panel on climate change (IPCC) issued a report in 2014 that attached probabilities to the predictions and statements made. Which prediction/statement was considered "very unlikely?"
relative to 1850- 1900, the global surface temperature for the end of the 21st century (2081-2100) will exceed 2 deg C
which is not a mixture?
sodium chloride
which pollutant is present in air as particulate matter
soot
green chemistry is
the design of products and processes that reduce hazardous substances
the montreal protocol is a
treaty to reduce the amount of CFCs produced in the world
even thought the concentration of air pollution has gone down over time, people in some metropolitan areas still breathe air that contains unhealthy levels of pollutants
true
DNA, the genetic material of living organisms, is damaged by the light in the
ultraviolet region, especially below a wavelength of 320 nm.
which country has the highest per capita emission of carbon dioxide
united states
Calculate the wavelength of a photon of electromagnetic radiation with a frequency of 1 MHz.
300 m
how many bromide ions can combine with one ion of aluminum to form an ionic compound?
3
rank these substances in order of their abundance in the air you breathe.
(most abundant)O3<CO2<Ar<O2<N2 (least abundant)