CHEM 140 Final
There are_____ σ and_____ π bonds in the H₂C=CH₂ molecule.
5 and 1
When an electron moves from the n = 3 orbit to the n = 2 orbit of a hydrogen atom, what wavelength of light is emitted?
656 nm
How many mm Hg are in 0.890 atm of pressure?
676 mm Hg
The halogens have how many valence electrons?
7
A sample of nitrogen gas occupies 9.20 L at 21 °C and 0.959 atm. If the pressure is increased to 1.15 atm at constant temperature, what is the newly occupied volume?
7.67 L
What is the pressure for STP conditions?
760 mm Hg
The octet rule states that atoms tend to gain, lose, or share electrons until they have _____ valence electrons.
8
The octet rule states that main group elements in the periodic table react to achieve a filled valence shell which consists of how many electrons?
8
A sample of Helium gas (2.35 mol) occupies 57.9 L at 300.0 K and 1.00 atm. The volume of this sample is ____L at 423 K and 1.00 atm.
81.6
The heating curve shown was generated by measuring the heat flow and temperature for a solid as it was heated. The slope of the segment corresponds to the heat capacity of the liquid of the substance.
CD
Which compound below is not capable of forming hydrogen bonds?
CH₄
Which alkane would have a lower boiling point?
CH₄ (Methane)
A gas sample with a mass of 88.0 mg occupies 50.0 mlat 750 Torr and 27 degrees Celsius. The gas is _____,
CO₂
Which compound below has the largest lattice energy?
CaO
What happens to the freezing point of water when ethylene glycol is added?
Ethylene glycol will interfere with the organization of water molecules during the freezing process therefore reducing the freezing point of water.
The principal source of the difference in the normal boiling points of ICI (97°C; molecular mass 162 amu) and Br₂ (59°C; molecular mass 160 amu) is both dipole-dipole interactions and London dispersion forces.
False
Which of the following halogens would have stronger intermolecular forces?
I₂
Which of the following molecules would have weaker intermolecular forces?
I₂
The kinetic-molecular theory of gases states that the average kinetic energy of the gas particles is proportional to the of the gas.
Kelvin temperature
Which force below increases in strength as the molecular weight of the compound increases?
London dispersion forces
Which molecule below has an unpaired electron?
NO
The correct order of increasing first ionization energy (smallest 7 largest) is
Na < Al < Ca < Sn.
Which molecule below violates the octet rule?
PF₅
Which statement best describe the structure of a carbonate anion?
The electron geometry of carbon in a carbonate anion is trigonal planar with a sp² hybridization and bond angles are 120°. There is a π~bond formed between a nonhybridized "C" p~orbital overlapping with an "O" p-orbital.
Based on valence bond theory, which statement best describes the electron geometry, bonding and hybridization of the central atom in carbon tetrachloride?
The electron geometry of carbon in carbon tetrachloride is tetrahedral with a sp³ hybridization. The C~CI bond is of α~character.
Based on valence bond theory, which statement best describes the electron geometry and hybridization of the central atom(s) in acetylene, H₂C=CH₂ ?
The electron geometry of the 2 carbons in acetylene is linear with a sp hybridization.
Using VSEPR theory, predict the molecule shape of a molecule that contains 2 electron groups.
linear
What is the molecular shape of CO₂ (Carbon dioxide)?
linear
According to the octet rule, a magnesium atom has a tendency to
lose two electrons
Which of these is NOT a unit used to measure gas pressure?
pound
N and L are the principal and angular momentum quantum numbers. When N = 3, the allowed values of L are
0, 1, and 2.
The concentration of KBr in a solution prepared by dissolving 2.13 g of KBr in 897 g of water is _____ molal.
0.0200
How many moles of CO₂ gas are present in a 9.1 L container at 25 °C and 1.35 atm?
0.502 moles
There is/are_____ σ bond(s) in the molecule below.
12
The angles between sp² orbitals are _____
120°
A gas originally at 27°C and 1.00 atm pressure in a 3.9 L flask is cooled at constant pressure until the temperature is 11°C. The new volume of the gas is ___ L.
3.7
Which of the following substances would be a poor choice for making conductive solutions?
C₆H₁₂O₆, CH₃OH, CH₃CH₂OH
On the phase diagram shown above, segment corresponds to the conditions of temperature and pressure under which the solid and the gas of the substance are in equilibrium.
AC
What predominate intermolecular force is in CH₃CH₂CH₃?
London forces
What predominate intermolecular force is in CO₂ (Carbon dioxide)?
London forces
"No two electrons in an atom may have the same values for all four quantum numbers" is
Pauli's Exclusion Principle.
Which statement accurately depicts what happens to water on the molecular level in a tea pot when it begins to boil?
The molecules begin to move farther apart decreasing their intermolecular forces and they escape the liquid state to enter the gas state.
The "rainbow of colors" produced by sunlight striking a prism is called
a continuous spectrum.
Based off periodic trends, which of the following has the strongest lattice energy?
aluminum chloride
For an experiment, you are asked to prepare a 2 m strong electrolytic solution. Which of the following salts would you use?
an alkali salt
Which of the following is a colligative property?
boiling~point elevation
Based on valence bond theory, what is the hybridization of the central atom(s) in C₂F₄ (tetrafluoroethene)?
both carbons are sp²
How would you increase the concentration of a 1 M NaCl (sodium chloride) solution?
bring the solution to near boiling until desired volume is achieved
Which type of solution has a higher osmotic pressure than that within cells?
hypertonic
Which type of solution has a lower osmotic pressure than that within cells?
hypotonic
Which statement best describes a bond forming between fluorine and iodine?
fluorine is more electronegative than iodine so it will attract the electron density in the bond giving rise to a polar bond
When four atomic orbitals are mixed to form hybrid orbitals, how many hybrid orbitals are formed?
four
Which phases change is an exothermic process?
freezing
According to the octet rule, a bromine atom has a tendency to
gain one electron.
Based off the molecular polarity of water, which of the following molecules would be soluble in water?
glucose, methanol, and ethanol
The lowest energy state of a hydrogen atom is called its state.
ground
The energy of a photon divided by its frequency equals
h Planck's constant.
The two types of chemical bonds commonly found in compounds are
ionic and covalent.
The minimum energy needed to remove an electron from an atom in its ground state is called the atom's
ionization energy.
At high altitudes, the boiling point of water is
less than 100 degrees Celsius.
Using VSEPR theory, predict the electron group geometry, molecular shape, and the bond angles in a molecule that contains 5 electron groups (2 bonds and 3 lone pair electrons).
trigonal bipyramidal, linear, 180°
Using VSEPR theory, predict the molecular shape and bond angles in BCl₃ ~ Boron Chloride.
trigonal planer, 120°
The temperature and pressure at which all three phases exist simultaneously is called the_________ point of a substance.
triple
Neon gas undergoes effusion _____ krypton gas does.
twice as fast as
The carbon disulfide (CS₂) molecule has
two double bonds.
The resistance of a liquid to flow is called the _____ of the liquid.
viscosity
Two ions are isoelectronic if they have the same
number of electrons.
Avogadro's Law states that the volume of a sample of a gas is proportional to the ___ of the gas.
number of moles
In order to produce sp³ hybrid orbitals, _____s atomic orbital(s) and _____ p atomic orbital(s) must be mixed.
one, three
In order to produce sp² hybrid orbitals, _____s atomic orbital(s) and _____ p atomic orbital(s) must be mixed.
one, two
When a transition metal atom forms a +1 ion, it loses an electron from what type of orbital?
s
A covalent bond is formed when two atoms
share one or more pairs of electrons with each other.
When three atomic orbitals are mixed to form hybrid orbitals, how many hybrid orbitals are formed?
three
Which of the following is an ionic compound?
Na₂O ~ Sodium oxide (metal, non~metal)
Which of the following pairs of elements can be joined by a covalent bond?
Nitrogen and Carbon
A diatomic molecule with a triple covalent bond is
N₂ ~ Nitrogen gas
Which of the following molecules has the greatest bond energy?
N₂ ~ nitrogen gas
A __________ is an instrument used to measure atmospheric pressure specifically in the area of meteorology.
barometer
At what temperature does salt water freeze?
below 0°C
p orbitals are shaped like
dumbbells.
The energy change that occurs when an electron is added to an atom is called the atom's
electron affinity.
Which of the following is a not a colligative property?
temperature of a solution
Using VSEPR theory, predict the electron group geometry, molecular shape, and the bond angles in a molecule that contains 4 electron groups (3 bonds and 1 lone pair electrons).
tetrahedral, trigonal pyramidal, <109.5°
What is the electron group (EG) and molecular geometry (MG) of an ammonium ion?
(EG) tetrahedral and (MG) tetrahedral
What is the electron group (EG) and molecular geometry (MG) of an ammonia molecule?
(EG) tetrahedral and (MG) trigonal pyramidal
The formal charge on the nitrogen atom in the nitrate ion (NO₃¹⁻ ) is
+1
The only allowed values for the spin magnetic quantum number are
+1/2 and -1/2.
The noble gases
- are monatomic - have filled s and p subshells - are generally unreactive - All of the above.
A typical double bond _____.
- is stronger and shorter than a single bond - consists of one a bond and one π bond - imparts rigidity to a molecule - consists of two shared electron pairs - All of the above answers are correct.
There is/are _____ π bond(s) in the molecule below.
1
What mass of nitrogen is needed to fill an 855 L tank at STP?
1.07 kg
Which salt would lower the freezing point of a solvent the most?
1.25m Na₂SO₄
How many psi are in 760 mm Hg?
1.47 x 10¹ psi
According to valence bond theory, which orbitals overlap in the formation of the bond in HBr?
1s on H and 4p on Br
There is/are _____ π bond(s) in the molecule below.
2
A tank containing both HF and HBr gases developed a leak. The ratio of the rate of effusion of HF (Hydrogen Fluoride) to the rate of effusion of HBr (Hydrogen Bromide) is
2.01
Oxygen gas (P o₂ = 1.10 atm), nitrogen gas (P N₂ = 0.840 atm), and carbon dioxide gas (P co₂= 0.125 atm) occupy the same container. What is the total pressure in the container?
2.07 atm
What is the pressure in a 5.80 L container that has 0.545 moles of oxygen gas at 22.0 °C?
2.28 atm
The Henry's law constant for helium gas in water at 30°C is 3.70 x 10⁻⁴ M/atm. When the partial pressure of helium above a sample of water is 0.650 atm, the concentration of helium in the water is ___ M.
2.41 x 10⁻⁴
The density (in g/L) of CO₂~carbon dioxide at 1140 torr and 60.0°C is
2.42
The average tire pressure for an automobile is 38.5 psi which is how many atmospheres of pressure?
2.62 atm
What is the volume for 1.00 mole of gas at STP?
22.4 L
The sp² atomic hybrid orbital set accommodates _____ electron domains.
3
There are _____ σ and _____ π bonds in the H-C=C-H molecule.
3 and 2
How many polar bonds does CCl₄ (Carbon Chloride)have in its structure?
4
A container filled with neon and argon gas is 25.00% by volume neon. What is the partial pressure of argon if the total pressure inside the container is 5.500 atm?
4.125 atm
A sample of 2.0 moles of nitrogen (N₂) gas at STP occupies a volume of _____liters.
44.8
A sample of 4.0 grams of methane (CH₄) gas at STP occupies a volume of _____liters.
5.6
286 L of hydrogen gas at STP reacts with excess chorine gas. What is the maximum amount of gas product that can be formed at STP?
572 L
The Lewis symbol for a sulfur atom includes how many dots?
6
The sp³d² atomic hybrid orbital set accommodates _____ electron domains.
6
The total number of π bonds in the H C=C C=C C=N molecule is __
6
There are_____ σ and_____ π bonds in the H₂C=C=CH₂ molecule.
6, 2
As a helium~filled balloon rises, its volume increases. This is an example of
Boyle's Law.
The bond angles in CH₄ (methane), NH₃ (ammonia), and H₂O (water) are 109.5°, 107°, and 104.5°, respectfully. Which of the statements best describes the variance in bond angles?
CH₄ (Methane) has no lone pairs of electrons on the central atom so the optimal molecular shape would be tetrahedral with bond angles of 109.5°. In NH₃ (ammonia) and H₂O (water) there are 1 and 2 lone pairs, respectfully, so more repulsion exists between the bonds and lone pairs, as a result, the bond angles are less than 109.5°.
According to VSEPR theory, the shape of an ammonium ion, NH₄⁺, is most similar to
CH₄, methane
28.5 L of an unknown gas has a mass of 55.92 g at STP. What is the identity of the unknown gas?
CO₂~carbon dioxide
Assuming all the salts below are the same concentration, which salt would lower the freezing point of water the most?
CaCl₂ (Calcium Chloride)
On a very cold day, you notice that your tires look a bit deflated than warmer days. This observation can be explained by.
Charles law
A balloon filled with hot air rises. This is an example of
Charles's Law.
"It is impossible to simultaneously know both the position and the momentum of an electron in an atom" is
Heisenberg's Uncertainty Principle.
Which force below is the strongest intermolecular attractive force?
Hydrogen bonding
Patients who enter the emergency room dehydrated are usually given sterile saline solution intravenously. The solution administered is isqtonic to prevent cell damage. What would happen if the solution was hypotonic?
Hypotonic solutions have a lower osmotic pressure than that within cells so hemolysis can occur.
Which compound below has the highest boiling point?
H₂0
Which choice below correctly lists the elements in order of increasing electronegativity (least 7 most) ? (all)
I< Br < Cl < F
Construct the molecule IF₅ and PF₅. How do the molecular shapes differ?
In IF₅ there is a lone pair of electrons on iodine where as in PF₅ there are no lone pairs on phosphorus. As a result, the molecular shape of IF₅ is square pyramidal and PF₅ is trigonal bipyramidal.
The correct order of increasing atomic radius (smallest 7 largest) is
Mg < Na < K < Rb.
Which of the following would conduct electricity?
NaCl solution
If it takes you 10 min. to boil an egg to perfection at sea level, how long would it take to boil an egg to your taste in the Carpathian Mountains at elevations of 8,500 ft?
The boiling point of water in the Carpathian Mountains is less than 100 °C because of lower atmospheric pressure which results in reduced intermolecular forces, so it would take a longer time to boil the egg.
Standard temperature and pressure (STP) equals (X) atmosphere(s) and (Y) degrees Celsius.
X = 1, Y = 0
lsopropyl alcohol feels cool to the touch because it has an (X) heat of (Y).
X = endothermic, Y = vaporization
A gas is most likely to exhibit ideal behavior at (X) temperature and (Y) pressure.
X = high, Y = low
The effective nuclear charge felt by an atom's valence electrons (X) going from left to right and (Y) going down a column on the Periodic Table.
X = increases Y = increases
Which gas below has the greatest density at STP?
Xe
The electron configuration of a copper atom is
[Ar] 4s¹ 3d¹⁰.
The electron configuration of a carbon atom is
[He] 2s² 2p².
The hydrogen cyanide (HCN) molecule has
a single bond and a triple bond.
If you want to boil a pot of water containing salt, at what temperature would boiling begin?
above 100°C
Which of the following would be a weak electrolyte in solution?
acetic acid
The solubility of NaCH₃CO₂ in water is -1.23 g/ml. What would be the best method for preparing a supersaturated NaCH₃CO₂ solution?
add 130 g of NaCH₃CO₂ to 100 ml of H₂0 at 80°C while stirring until all the solid dissolves, then let the solution cool to room temperature.
Suppose your car is equipped with tire pressure monitoring system (TPMS) and the tire pressure is 34.0 psi on a 98 °F day in California. You decided to take a road trip to Alaska where the temperature drops to 20 °F. As you arrived in Alaska, you noticed that the tire pressure monitoring system alert light is illuminated. Why did this happen?
as temperature decreases, gas molecules lose kinetic energy and the volume of gas is reduced thus reducing the overall pressure in the tire which results in the TPMS to become activated
On a hot summer day, you notice that a bag of chips left in your vehicle has inflated. Why did this happen?
as temperature increases, gas molecules gain kinetic energy and the volume of gas increases inside the bag of chips
What is the relationship between pressure and volume of a gas at constant temperature?
as volume decreases, pressure increases
The wavelength of a photon multiplied by its frequency equals
c, the speed of light.
A typical triple bond _____.
consists of one a bond and two π bonds
The highest temperature at which a substance can exist in its liquid state is called its _____ point.
critical
What predominate intermolecular force is in HCI (Hydrogen Chloride)?
dipole~dipole
The energy required to cause a liquid to boil is called the _____ of the liquid.
heat of vaporization
What predominate intermolecular force is in CH₃OH (Methanol)?
hydrogen bonding
What predominate intermolecular force is in NH₃ (ammonia)?
hydrogen bonding
Substance X has a boiling point of 150 degrees F and a freezing point of 15 degrees F. The condensation point of X _____
is 150 degrees F
Which type of solution has the same osmotic pressure as that within cells?
isotonic
Water changing from ice to a liquid is an example of.
melting
The partial pressure of each gas in a mixture of gases is proportional to the of the gas.
mole fraction
Which of the following when dissolved in deionized water would make a poor conducting solution?
sugar
s orbitals are shaped like
spheres.
What is the molecular shape and polarity for xenon tetrafluoride?
square~planar and non~polar
Sodium chloride changing from a solid to a gas is an example of_________.
sublimation
Which of the following would be soluble in water?
sugar, NaCl, HCI
The pressure of a gas in a container is 1.85 atm and occupies a volume of 12.5 L. If the original volume is reduced by half at constant temperature, what would happen to the pressure?
the pressure would double
