CHM1020 Final Exam
A Big Mac has a nutritional value of 563 Calories (Cal). Express this value in Joules. (1 Cal = 1000 cal, 1 cal = 4.184 J)
2.36x10^6 J
Which of the following would be described as "fine particles"?
2.5 µmeter diameter soot
What is the pH of a solution with a [H+] of 1.7x10^-3 M?
2.8
A 4-L sample of water contains 80 µg of lead. What is this lead concentration, in parts per billion (ppb)?
20
A Big Mac has a nutritional value of 563 Calories. Assuming that all the energy produced from consuming the burger goes towards keeping your heart beating, approximately how many days can the Big Mac sustain a heartbeat of 82 beats/minute? (Note: 1 Cal = 1000 cal, 1 cal = 4.184 J, 1 heartbeat requires 1 J of energy)
20 days
If you have 200.0 g of radioisotope with a half-life of 5 days, how much isotope would remain after 15 days?
25.0 g
CO2 emissions in China declined by 9 percent over the five-year period ending in 2000. If 5.00x10^8 metric tons of (t) of CO2 was emitted in 1995, how much CO2 was in 2000?
4.55x10^8 t
What is the frequency of light with a wavelength of 6.34 nm?
4.73x10^14 Hz
What is the role of polar stratospheric clouds (PSCs) on the destruction of the ozone?
chemical reactions occur on the clouds that convert molecules that do no damage to those that deplete ozone
Which form of water disinfection continues to provide antibacterial protection after the water leaves the purification plant?
chlorination
P2O5 is the chemical formula for
diphosphorus pentoxide
The most numerous of the elements are the
metals
Which is the best representation showing a sodium cation in water?
(see image)
Which shows the Lewis structure of water with the correct partial charges and nonbonding electrons?
(see image)
Use the equation to help you calculate the heat of combustion of ethylene, C2H4. The bond energies are: C ---- H 416 kJ/mol; C ---- C 356 kJ/mol; C ---- C 598 kJ/mol; O ---- O 498 kJ/mol; C ----- O 803 kJ/mol; H Picture O 467 kJ/mol.
-1324 kJ/mol
A 3 L water sample taken from Flint, Michigan contained µg of dissolved lead ion. What is the lead ion concentration of the solution in ppm?
0.02 ppm
"Hard" water in parts of the Midwest may have a calcium ion concentration as high as 400 ppm. What is this calcium ion concentration when expressed as a percentage?
0.04 percent
Assume that coal can be represented by the chemical formula C135H96O9NS. If 15.0 tons of coal is burned, what mass of sulfur is formed in the SO2 produced by this process?
0.252 tons
A propane grill was used for an hour and produced 1.5 kg of carbon dioxide (CO2). What is the mass of carbon atoms produced in this amount of CO2?
0.41 kg
The numbers 1 through 4 are used to identify four different elements on the periodic table. Which element is expected to have 2+ charge when it forms an ion?
1
Choose the proper coefficients for each substance to balance this equation. ____ C2H4(g) + ____ O2(g) → ____ CO2(g) + ____ H2O(g)
1, 3, 2, 2
The majority of new smartphones being released have displays that are at least 5 inches in size. What is this size in centimeters? (There are 2.54 cm in one inch.)
12.7 cm
The history of average global temperature for the last 160,000 years is derived from isotopic analysis of ice layers in Antarctica. Scientists study the _____________ ratio in ____________.
1H/2H; H2O
Determine the molar mass of fluoxetine (C16H16F3NO), also known as Prozac
295.3 g/mo
What is the balanced chemical equation for the complete combustion of ethane (C2H6) to produce carbon dioxide and water?
2C2H6 (g) + 7O2 (g) --> 4CO2 (g) + 6H2O (g)
How many bromide ions can combine with one ion of aluminum to form an ionic compound?
3
The heat of combustion of butane (C4H10) is 91.4 kJ/g. How much heat is produced if 7.0 moles of butane undergoes complete combustion?
3.7x10^4 kJ
The recommended daily requirement of calcium is 1,000 mg. Tap water in a Midwestern city contains approximately 150 mg Ca/L. A person living in the city who drinks two liters of water in one day would receive _________ percent of his/her RDA of calcium.
30
Mannose (C6H12O6) is a simple sugar found in many fruits and vegetables. How many oxygen atoms are in 7.15x10^23 molecules of mannose?
4.29x10^24 O atoms
The pH of rain water falling through an unpolluted atmosphere is closest to
5.4
What mass of K2SO4 is required to make a 600.0 mL K2SO4 solution with a concentration of 0.50 M?
52 g
If a snack cake contains 450 food Calories and Dr. Wattenburger is able to burn 250 Calories by running for one-half an hour, how long must she run to completely burn off the snack cake?
54 minutes
How many protons are in an atom of carbon?
6
Hydrogen gas (H2) is a promising alternative to fossil fuels. How many molecules are present in 1.0 kg of hydrogen gas?
6.0x10^26
A hot dog has a nutritional value of 290 Cal. How many 20 kg dumbbells could be lifted 1 m off the floor with the amount of energy obtained from metabolizing one hot dog? (Note: it requires 200 J of energy to lift a 20 kg dumbbell 1 m off the floor; 1 Cal = 1000 cal; 1 Cal = 4.184 J)
6067
Express 750 nanometers in meters
7.5x10^-7 m
Which diagram(s) best represent(s) only molecules?
I and II only
Which of the following is a weak base?
NH3
The name of the compound formed by combining carbon atoms with oxygen atoms to form (O)(C)(O) is
carbon dioxide
What atmospheric component is responsible for the natural acidity of rain?
carbon dioxide
Currently, the primary source of sulfur dioxide emissions into the atmosphere is
coal burning power plants
A substance that can be broken down into two or more simpler substances by chemical methods is called a(n)
compound
During petroleum refining, catalysts play an extremely important role during the
cracking and reforming processes
Silicon has four electrons in its outer energy level, gallium has three. Adding small amounts of gallium to pure silicon
creates a p-type semiconductor
Rank the following solutions in order of increasing concentration: a. 32.3 g of NaCL in 100 mL of water b. 0.10 mol of NaCL in 10 mL of water c. 62.1 g of NaCL in 1 L of water d. 0.25 M NaCL solution
d < c < a < b
Identify the single most effective strategy to reduce carbon dioxide emissions.
develop alternate energy sources that do not rely on fossil fuels
Oxidation and reduction of atoms involves a change in the number of ___________ in the atom.
electrons
Which of the following is not an advantage of location wind turbines off-shore instead of on land?
maintenance costs are lower off-shore
Based on its name, which carbon compound contains the fewest carbon atoms?
methane
Combustion is a chemical process in which a fuel combines with ________ to release energy and form products.
oxygen
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 trioxide?
particles of ash
A disadvantage of ozonation over chlorination is
the higher cost of ozonation and ozonation does not protect the water after the initial process is complete
Which of the following hydrocarbons would have the highest boiling point?
the largest diagram
Which Lewis structure for formaldehyde (CH2O) is correct?
the option with 12 valence electrons (D)
Which common process on earth is endothermic?
the production of oxygen by photosynthesis
When assessing the risk of an air pollutant, which does not play a role in considering someone's exposure to the pollutant?
the toxicity of the pollutant
Determine the shape or geometry of PH3. (Hint: Use the Periodic Table to arrive at the electron configuration for phosphorous.)
trigonal pyramidal
What color of visible light has the highest frequency?
violet
What color of visible light has the shortest wavelength?
violet
Why is water a liquid at room temperature instead of a gas?
water has hydrogen between the molecues
Which is not a consequence of hydrogen bonding between water molecules?
water is colorless and odorless
Which of the following molecules are polar? a. H2S b. CO2 c. BCl3 d. H2O
a,d
Choose the proper coefficients for each substance to yield a balanced equation
2, 1, 2
Evaluate the ratio MH+ (pH 3) / MH+ (pH 7).
10,000
Which is not a pure substance?
Air
HFCs may be used to replace CFCs. Which compound is a HFC?
CF3CH2F
Catalytic converters reduce the amount of __________ in car exhaust.
CO
Which component of the air makes up approximately 100 times more of an exhaled breath than of an inhaled breath?
CO2
What is the chemical formula for carbon disulfide?
CS2
Which country is the world's leading producer of rare earth elements?
China
Which diagram(s) best represent(s) only individual atoms?
III only
Which concentration is consistent with a basic solution?
MOH- = 3.4x10^-3 M
Oxygenated gasolines are blends of petroleum-derived compounds with oxygen-containing compounds. Which of the following oxygenated compounds has been discontinued in some states because of potential health risks?
MTBE
Which chemical equation shows the dissociation of magnesium hydroxide?
Mg(OH2) --> Mg2+ + 2OH-
Which compounds are used in mineral-based sunscreens?
ZnO and TiO2
What type of radiation is given off in this nuclear reaction?
alpha
What is the relationship between stratospheric levels of atomic chlorine and ozone?
as chlorine increases, ozone decreases
The majority of N2O molecules in the atmosphere come from
bacterial removal of nitrate ions (NO3-) from soil
Light behaves like
both a particle and a wave
Radioactive forcings are
factors that influence the balance of Earth's incoming and outgoing radiation
Single bonds, double bonds, and triple bonds
have 2, 4 and 6 shared electrons, respectively
In an exothermic chemical reaction
heat is released as the reaction proceeds
Free radicals are
highly reactive chemical species, species with unpaired electrons, species such as H• and •OH
In order to make useful predictions, which factors must be accounted for by climatic models? i. Cooling effect of atmospheric aerosols ii. Smoke, haze, and cloud cover iii. Change in land use iv. Combustion of fossil fuels
i, ii, iii, and iv
Which is not true of radioactive half-life? Radioactive half-life is
increased by heating the isotope
Decreased stratospheric ozone concentrations may lead to
increased incidences of melanomas, harm to young marine life, an increased occurrence of cataracts
Water has one of the highest specific heats of any known liquid. This means that the temperature of a water sample __________ with the input of a ____________ amount of energy.
increases only slightly; largef
Electronegativity
is a measure of an atom's attraction for an electron in a chemical bond
What is the effect of the absorption of infrared energy on matter?
it increases the vibration of chemical bonds
Which unit is commonly used by utilities to measure the amount of electrical energy consumed?
kWh
In a solar cell, semiconductors of the p-type and n-type are placed in contact with each other via a conducting wire. In order to generate an electric current, which of the following must be true?
light shining on the system must have enough energy to set electrons in motion from the n-type semiconductors to the p-type
When the ______ molecules of ethanol, C2H5OH, are added to water, the ethanol molecules _______.
polar; form hydrogen bonds with the polar water molecules
The energy stored in the chemical bonds of fossil fuels is a form of ______ energy.
potential
We cannot effectively clean nonpolar substances from our hands or clothing with water alone; we must add soap or detergent. The structure of a typical soap molecule is shown below. Which region of this molecule would dissolve in a nonpolar substance such as grease?
region 1
At water treatment plants aluminum sulfate and calcium hydroxide are added to
remove suspended clay and dust particles
Which is not a mixture?
sodium chloride
Which is a common characteristic of both nuclear and conventional electric power plants?
steam turbines
The property of matter that determines the direction of heat flow is the
temperature
Which is a known risk associated with nuclear power plants?
the cooling water source can suffer thermal pollution
In metropolitan areas, the concentration of ozone in the atmosphere drops at night. Why?
the formation of ozone requires sunlight