chm 2045 final
What is the wavelength (in m) of a pitched baseball with a mass of 0.120 kg and a speed of 44.7 m/s? A) 6.24 × 10^‒34 m B) 1.50 × 10^‒36 m C) 1.24 × 10^‒34 m D) 0.76 ×10^‒34 m E) 6.24 ×10^‒36 m
1.24 × 10^‒34 m
The electron configuration of the chromium(II) ion (Cr2+) is__________.
1s22s22p63s23p63d4
Calculate the wavelength of light emitted (in m) when an electron in the hydrogen atom makes a transition from an orbital with n = 5 to an orbital with n = 3. A) 1.28 × 10^-6 m B) 6.04 × 10^‒7 m C) 2.28 × 10^‒6 m D) 1.55 × 10^‒19 m E) 4.62 × 10^‒26 m
A) 1.28 × 10^‒6 m
Which of the following is the best description of a state function? A) A property whose value does not depend on the path taken. B) A property whose value depends on the path taken. C) A property whose value depends on the size of the object. D) A property whose value depends on how fast the reaction occurs. E) A property whose value depends on the standard states.
A) A property whose value does not depend on the path taken.
. Which of the following chemical symbols is NOT correctly paired with its name? A) Ar = arsenic B) Be = beryllium C) F = fluorine D) Mn = manganese E) Sn = tin
A) Ar = arsenic
Vinegar is a dilute solution of acetic acid. The molar mass of acetic acid is 60.0 g/mol and it has an empirical formula of CH2O. What is the molecular formula of acetic acid? A) C2H4O2 B) CH2O C) C2H4O D) CH4O E) C2HO2
A) C2H4O2
What is the formula for carbon disulfide? A) CS2 B) C2S C) CSi D) CaS2 E) (CS)2
A) CS2
Consider the Lewis structure for HCN. Determine the hybridization of the carbon atom. Then determine the total number of sigma (σ) and pi (π) bonds in the molecule. A) Carbon hybridization= sp3, 3 σ bonds; 2 π bonds B) Carbon hybridization= sp3, 4 σ bonds; 1 π bond C) Carbon hybridization= sp, 2 σ bonds; 2 π bond D) Carbon hybridization= sp2, 3 σ bonds; 1 π bond E) Carbon hybridization= sp2, 3 σ bonds; 2 π bonds
A) Carbon hybridization= sp, 2 σ bonds; 2 π bond
What is the identity of a gas that has a density of 1.4975 g/L and a volume of 8.64 L at a pressure of 2.384 atm and with a temperature of 349.6 Kelvin? A) H2O B) N2 C) SO2 D) NO3 E) Cl2
A) H2O
Identify the element that has a ground state electron configuration of [Kr]5s24d 5. A) Tc B) Mn C) Nb D) Ru E) I
A) Tc
Why does the ideal gas law fail at high pressures? A) Collisions between gas particles become less important. B) Collisions between gas particles are no longer inelastic. C) The volume of the gas particles decreases. D) The volume of the gas particles becomes more important. E) The ideal gas law fails at low temperatures, not at high pressures.
A) The volume of the gas particles becomes more important.
What ions does Li2CO3 dissociate into in water? A) Li2CO3 only B) 2 Li+, C4+ and O2− C) Li2+, C4+ and O2− D) 2 Li+ and CO32− E) Li2+ and CO32−
D) 2 Li+ and CO32−
What is the oxidation state of chlorine in ClO3−? A) +7 B) +5 C) +3 D) +1 E) −1
B) +5
. In an acid-base titration performed to determine the unknown molarity of an acid, 30.2 mL of 0.100 M NaOH was required to neutralize 25.0 mL of H2SO4. What is the molarity of the acid? 2 NaOH(aq) + H2SO4(aq) ® Na2SO4(aq) + 2 H2O(l) A) 0.00302 M B) 0.0604 M C) 0.121 M D) 0.242 M E) 1.52 M
B) 0.0604 M
5. A stock solution of HNO3 has a molarity of 14.9 M. If 25.0 mL of the stock solution is diluted to a final volume of 0.500 L, what is the molarity of the final diluted solution? (1L = 1000 mL) A) 0.298 M B) 0.745 M C) 1.34 M D) 298 M E) 745 M
B) 0.745 M
. A beam of light has a frequency of 1.20 × 1013 s−1. What is the wavelength of the light in m? A) 0.0400 m B) 2.50 × 10−5 m C) 25.0 m D) 2.5 m E) 12.0 m
B) 2.50 × 10^−5 m
Lithium has two naturally occurring isotopes, 6Li (isotopic mass = 6.015121 amu) and 7Li (isotopic mass = 7.016003 amu). Lithium has an atomic mass of 6.9409 amu. What is the percent abundance of lithium-6? A) 6.08% B) 7.50% C) 46.2% D) 86.7% E) 92.5%
B) 7.50%
Identify the oxidizing agent in the following chemical reaction: NO(g) + 2 H2O(l) + 3 Ag+(aq) → NO3-(aq) + 4 H+(aq) + 3 Ag(s) A) NO B) Ag+ C) NO3− D) Ag E) Not a redox reaction
B) Ag+
Which of the following correctly identifies the balanced net ionic equation and spectator ions that result when CaCl2 reacts with NaOH? Balanced Net Ionic Equation Spectator Ions A) CaCl2(aq) + 2NaOH(aq) → CaOH(s) + NaCl(aq) Ca2+, Na+, OH-, Cl- B) Ca2+(aq) + 2OH-(aq) → Ca(OH) 2(s) Na+, Cl- C) Ca2+(aq) + 2OH-(aq) + 2 Na+(aq) + 2 Cl-(aq) → Ca(OH) 2(s) Ca2+, OH- D) Ca2+(aq) + 2OH-(aq) + Na+(aq) + Cl-(aq) → Ca(OH) 2(s) Ca2+, OH- E) Ca2Cl(aq) + 2NaOH(aq) → Ca(OH)2(s) + 2NaCl(aq) Na+, Cl-
B) Ca2+(aq) + 2OH-(aq) → Ca(OH) 2(s) Na+, Cl-
The specific heat of copper metal is 0.385 J/g•°C. How many joules of heat are necessary to raise the temperature of a 1.42-kg block of copper from 25.0 °C to 88.5 °C?
D) 3.47 × 104 J
. Which of the following correctly explains how the Bohr model and quantum mechanical model are different? I. The Bohr model accounts for the emission spectrum of hydrogen, but the quantum mechanical model does not. II. The Bohr model has electrons moving around the nucleus in circular orbits, but the quantum mechanical model does not. III. The Bohr model species precise values for the energies of electrons, but the quantum mechanical model does not.
B) II only
Which of the following statements is/are TRUE? I. Electrons make up most of the mass of an atom. II. Neutrons and protons are found in the nucleus of an atom. III. Protons and neutrons have charges that are opposite in sign but equal in magnitude. A) I only B) II only C) III only D) both II and III E) none of them
B) II only
. How would you describe the molecular polarity of SeCl6? A) Nonpolar, because Se-Cl is a nonpolar bond and there is no lone pair on Se B) Nonpolar, because Se-Cl is a polar bond, but the geometry is symmetric C) Polar, because Se-Cl is a polar bond although the geometry is symmetric D) Polar, because Se-Cl is a polar bond and there is a lone pair on Se E) Polar, because Se-Cl is a nonpolar bond but there is a lone pair on Se
B) Nonpolar, because Se-Cl is a polar bond, but the geometry is symmetric
Which of the following statements is TRUE about the relative atomic size of Mg and P? A) P atom is smaller than the Mg atom since P has a smaller ionization energy. B) P atom is smaller than the Mg atom since P has a larger effective nuclear charge. C) P atom is smaller than the Mg atom since P has more shielding for its outermost electrons. D) P atom is larger than the Mg atom since P has more electrons. E) P atom is larger than the Mg atom since P has more energy levels (n).
B) P atom is smaller than the Mg atom since P has a larger effective nuclear charge.
Use the information provided to determine ΔH°rxn for the following reaction: CH4(g) + 3 Cl2(g) → CHCl3(l) + 3 HCl(g) ΔH°f (kJ/mol) CH4(g) −75 CHCl3(l) −134 HCl(g) −92 A) −151 kJ B) −335 kJ C) +662 kJ D) +117 kJ E) −217 kJ
B) −335 kJ
Given the chemical reaction: C + 2 H2 → CH4 has a ΔH = −74.9 kJ, what is the change in heat (in kJ) if 35.0 g of H2 is reacted with excess C? A) −218 kJ B) −650. kJ C) −1.30 × 103 kJ D) −2620 kJ E) −5240 kJ
B) −650. kJ
How many moles of carbon atoms are present in 1.50 g of C2H6O? The molar mass of C2H6O is 46.07 g/mol. A) 0.0145 mol C B) 0.0326 mol C C) 0.0651 mol C D) 30.7 mol C E) 69.0 mol C
C) 0.0651 mol C
What is the mass (in g) of CO2 gas produced by reacting 40.00 g of C3H8 with excess O2 gas according to the following balanced chemical equation? (The molar mass of C3H8 is 44.10 g/mol, and the molar mass of CO2 is 44.01 g/mol.) C3H8 (g)+5 O2 (g)→3 CO2 (g)+4 H2O (g) A) 13.30 g B) 39.93 g C) 119.8 g D) 120.2 g E) 132.4 g
C) 119.8 g
What is the molarity of a NaOH solution that is prepared by dissolving 20.0 g of NaOH in 250. mL of water? The molar mass of NaOH is 40.0 g/mol. A) 0.002 M B) 0.080 M C) 2.00 M D) 80.0 M E) 200. M
C) 2.00 M
What is the change in internal energy (ΔE or ΔU ) for a system that is absorbing 325 J of heat and is performing 10 J of work on the surroundings? A) −335 J B) - 315 J C) 315 J D) 325 J E) 335 J
C) 315 J
. Determine the number of protons, neutrons, and electrons in Se2− if its mass number is 75. A) 34 protons, 41 neutrons, 34 electrons B) 34 protons, 43 neutrons, 32 electrons C) 34 protons, 41 neutrons, 36 electrons D) 32 protons, 43 neutrons, 34 electrons E) 36 protons, 39 neutrons, 38 electrons
C) 34 protons, 41 neutrons, 36 electrons
How many N atoms are present in 76.3 g of N2O4? The molar mass of N2O4 is 92.02 g/mol. A) 4.99 × 1023 N atoms B) 7.26 × 1023 N atoms C) 9.99 × 1023 N atoms D) 1.38 × 1024 N atoms E) 5.54 × 1025 N atoms
C) 9.99 × 1023 N atoms
What is the empirical formula for a compound based on the following elemental mass percent composition: C 49.48%, H 5.19%, N 28.85%, O 16.48%? A) CHNO B) CH5N2O C) C4H5N2O D) C4H3NO2 E) C12H4N7O4
C) C4H5N2O
An atom has 28 neutrons and a mass of 52 amu. What element is the atom? A) Ni B) Te C) Cr D) Hg E) Not enough information
C) Cr
1. Suppose a metal will eject electrons from its surface when struck by yellow light. What will happen if the surface is struck with UV light? A) No electrons would be ejected. B) Electrons would be ejected, and they would have the same kinetic energy as those ejected by yellow light. C) Electrons would be ejected, and they would have greater kinetic energy than those ejected by yellow light. D) Electrons would be ejected, and they would have lower kinetic energy than those ejected by yellow light. E) Not enough information to determine.
C) Electrons would be ejected, and they would have greater kinetic energy than those ejected by yellow light.
Which of the following is a balanced reaction that describes H2SO4 and KOH mixed? A) H2SO4 (aq) + KOH (aq) à KSO4 (aq) + H2O (l) B) H2SO4 (aq) + KOH (aq) à KSO4 (aq) + H3O (l) C) H2SO4 (aq) + 2 KOH (aq) à K2SO4 (aq) + 2 H2O (l) D) H2SO4 (aq) + 2 KOH (aq) à K2SO4 (aq) + 4 H2O (l) E) H2SO4 (aq) + KOH (aq) à K2SO4 (aq) + H2O (l)
C) H2SO4 (aq) + 2 KOH (aq) à K2SO4 (aq) + 2 H2O (l)
Which of the following statements about isotopes is/are TRUE? (I) Isotopes of the same element differ only in the number of electrons they contain. (II) Isotopes of the same element have the same mass. (III) Isotopes of the same element have the same number of protons but a different number of neutrons. A) I only B) I and II C) III only D) II and III E) All statements are true.
C) III only
Which of the following has a longer wavelength than infrared radiation? A) X-ray B) Ultraviolet C) Microwave D) Gamma ray E) Visible
C) Microwave
. Determine the limiting reactant and the mass (in g) of N2 that can be formed from 50.0 g N2O4 and 45.0 g N2H4. N2O4 molar mass = 92.02 g/mol; N2H4 molar mass = 32.05 g/mol; N2 molar mass = 28.02 g/mol. N2O4(l) + 2 N2H4(l) → 3 N2(g) + 4 H2O(g) Limiting Reactant Amount of N2 Formed A) N2H4 13.3 g B) No limiting reactant 45.0 g C) N2O4 45.7 g D) N2H4 59.0 g E) N2O4 105 g
C) N2O4 45.7 g
Determine the electron geometry (eg) and molecular geometry (mg) of SF4. A) eg=trigonal bipyramidal, mg=trigonal bipyramidal B) eg=tetrahedral, mg=tetrahedral C) eg=trigonal bipyramidal, mg=see-saw D) eg=octahedral, mg=trigonal bipyramidal E) eg=octahedral, mg=octahedral
C) eg=trigonal bipyramidal, mg=see-saw
When heat is absorbed by the system from the surroundings, the process is said to be ____, and the sign of process is _______. A) exothermic; positive B) exothermic; negative C) endothermic; positive D) endothermic; negative E) exothermic; zero
C) endothermic; positive
Which of the following is the correct name for the compound Mn2O3? Mn is a metal with a variable charge. A) dimanganese trioxide B) manganate ion C) manganese(III) oxide D) manganese(II) oxide E) manganese oxide
C) manganese(III) oxide
Consider the chemical reaction: 2 Cu(NO3)2(s) → 2 CuO(s) + 4 NO2(g) + O2(g) When 9.378 g of Cu(NO3)2 completely decompose, how many liters of gases will be produced at 273 K and 1 atm? The molar mass of Cu(NO3)2 is 187.56 g/mol. A) 0.56 B) 1.12 C) 2.24 D) 2.80 E) 3.92
D) 2.80
What is the formal charge for a nitrogen atom that has a triple bond, a single bond, and no lone pairs on it? A) −3 B) −1 C) 0 D) +1 E) +3
D) +1
A mixture of N2, O2 and Ar have mole fractions of 0.25, 0.65, and 0.10, respectively. What is the partial pressure of N2 if the total pressure of the mixture is 3.9 atm? A) 2.5 atm B) 0.39 atm C) 0.67 atm D) 0.98 atm E) 1.33 atm
D) 0.98 atm
Coal gasification can be represented by the equation: 2 C(s) + 2 H2O(g) → CH4(g) + CO2(g) ΔH = ? Use the following information to find ΔH for the reaction above. CO(g) + H2(g) → C(s) + H2O(g) ΔH = −131 kJ CO(g) + H2O(g) → CO2(g) + H2(g) ΔH = −41 kJ CO(g) + 3 H2(g) → CH4(g) + H2O(g) ΔH = −206 kJ A) −15 kJ B) −116 kJ C) −372 kJ D) 15 kJ E) 116 kJ
D) 15 kJ
10. What is the stoichiometric coefficient for O2(g) when the following chemical equation is balanced using the lowest, whole-number coefficients? ___ C3H6(g) + ___ O2(g) → ___ CO2(g) + ___ H2O(g) A) 2 B) 3 C) 6 D) 9 E) 18
D) 9
. What is the mass percent of aluminum in Al(ClO3)3? A) 24.4 % B) 13.1 % C) 34.6 % D) 9.73 % E)14.9 %
D) 9.73 %
Five samples of copper, aluminum, iron, gold, and silver are at the same initial temperature with the same mass. Which sample will reach the highest temperature if they absorb the same amount of heat? Substance Cs, J/g °C Copper 0.385 Aluminum 0.903 Iron 0.449 Gold 0.128 Silver 0.235
D) Gold
Identify the gas particle that would travel the fastest at a temperature of 293 K. A) SO2 B) CO2 C) N2 D) Ne E) Ar
D) Ne
Which of the following is a nonmetal? A) Mg B) Si C) Al D) P E) K
D) P
1. Identify the following substances as atomic element, molecular element, molecular compound, or ionic compound. Substances: PbI4 and N2 A) PbI4 atomic element; N2 molecular compound B) PbI4 molecular compound; N2 molecular compound C) PbI4 ionic compound; N2 molecular compound D) PbI4 ionic compound; N2 molecular element E) PbI4 molecular element; N2 atomic element
D) PbI4 ionic compound; N2 molecular element
In a molecule of PClBr2, which statement best describes the bonding between P and Cl? A)The bonding between P and Cl is ionic with a formal positive charge on P. B)The bonding between P and Cl is ionic with a partial positive charge on P. C) The bonding between P and Cl is ionic with a partial positive charge on Cl. D) The bonding between P and Cl is polar covalent with a partial positive charge on P. E) The bonding between P and Cl is polar covalent with a partial positive charge on Cl.
D) The bonding between P and Cl is polar covalent with a partial positive charge on P.
Which of the following statements is TRUE? A) Electrons placed in antibonding orbitals stabilize the ion/molecule. B) The total number of molecular orbitals formed doesn't always equal the number of atomic orbitals in the set. C) A bond order of 0 represents a stable chemical bond. D) When two atomic orbitals come together to form two molecular orbitals, one molecular orbital will be lower in energy than the two separate atomic orbitals and one molecular orbital will be higher in energy than the separate atomic orbitals. E) All of the above are true.
D) When two atomic orbitals come together to form two molecular orbitals, one molecular orbital will be lower in energy than the two separate atomic orbitals and one molecular orbital will be higher in energy than the separate atomic orbitals.
The pressure of a sample of gas describes: A) the speed of the gas molecules B) the number of gas molecules C) the number of gas molecules in a set volume D) the force of gas molecules hitting the surface E) the mass of the gas molecules
D) the force of gas molecules hitting the surface
An ionic bond results from: A) the sharing of a pair of electrons B) the attraction of a proton and an electron C) the mutual association of two electrically neutral atoms D) the mutual attraction of a cation and an anion E) the sharing of a single valence electron
D) the mutual attraction of a cation and an anion
15. Determine the percent yield of a reaction that produces 28.65 g of Fe when 50.00 g of Fe2O3 react with excess Al according to the following reaction. (Molar masses: Fe = 55.85 g/mol, O = 16.00 g/mol, Fe2O3 = 159.70 g/mol) Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s) A) 20.02 %B) 28.65 %C) 57.30 %D) 61.03 %E) 81.92 %
E) 81.92 %
Which of the following correctly describes the resonance hybrid (actual structure) of CO32-? A) CO32- contains three single bonds. B) CO32- contains three double bonds. C) CO32- contains two single bonds and one double bond. D) CO32- contains three bonds that are equivalent to a bond order of 3/2. E) CO32- contains three bonds that are equivalent to a bond order of 4/3.
E) CO32- contains three bonds that are equivalent to a bond order of 4/3.
19. Select ALL Arrhenius acids from the following substances. NaCl HCl KOH NH3 HNO3 A) NaCl and KOH B) NaCl and HNO3 C) HCl, NH3, and HNO3 D) NH3 and KOH E) HCl and HNO3
E) HCl and HNO3
List the following compounds in order of decreasing magnitude of lattice energy: K2O, Rb2S, Li2O A) K2O > Li2O > Rb2S B) Rb2S > K2O > Li2O C) Rb2S > Li2O > K2O D) Li2O > Rb2S > K2O E) Li2O > K2O > Rb2S
E) Li2O > K2O > Rb2S
6. Which of the following reactions best describes what happens after mixing an aqueous solution of ZnCl2(aq) with an aqueous solution of (NH4)2S(aq)? A) ZnCl2(aq) + (NH4)2S(aq) → (NH4)2Cl2(aq) + ZnS(s) B) ZnCl2(aq) + (NH4)2S(aq) → 2 NH4Cl(aq) + ZnS(aq) C) ZnCl2(aq) + (NH4)2S(aq) → Cl2S(aq) + Zn(NH4)2(s) D) ZnCl2(aq) + (NH4)2S(aq) → Cl2S(s) + Zn(NH4)2(s) E) ZnCl2(aq) + (NH4)2S(aq) → 2 NH4Cl(aq) + ZnS(s)
E) ZnCl2(aq) + (NH4)2S(aq) → 2 NH4Cl(aq) + ZnS(s)
. Describe a pi bond. A) s orbital overlapping with d orbital B) end to end overlap of two s orbitals C) p orbital overlapping with f orbital D) overlap of any two hybrid orbitals E) side by side overlap of two p orbitals
E) side by side overlap of two p orbitals
10. What is the hybridization of the central atom in BrF5? A) sp B) sp2 C) sp3 D) sp3d E) sp3d2
E) sp3d2
An amount of solid barium chloride, 20.8 g, is dissolved in 100 g of water in a coffee-cup calorimeter by the reaction: BaCl2 (s) à Ba2+(aq) + 2Cl−(aq) The water is originally at 25.0 °C, and after the reaction, the temperature of the solution is 26.6 °C. What is the enthalpy change (ΔH) associated with the reaction as written? (Cs = 4.04 J/(g°C) for the solution) A) + 650 J B) −650 J C) −780 J D) −6500 J E) −7800 J
E) −7800 J