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Sodium azide decomposes rapidly to produce nitrogen gas. 2 NaN3(s) 2 Na(s) + 3 N2(g) What mass of sodium azide will inflate a 60.0 L airbag for a car to a pressure of 1.50 atm at 32 C? (R = […]

If an ionic solid has a face-centered cubic lattice of anions (Xn–) and all the octahedral holes are occupied by metal cations (Mm+), what is the formula for the compound? A.M2X B.MX C.MX2 D.M2X3 E.M3X2 A 25.0 mL sample of […]

A sample of phosphorus-32 is found to have an activity of 885 disintegrations per hour (dph). After 25 hours the activity has decreased to 841 dph. What is the rate constant for the decay of phosphorus-32? A.0.0038 hr“1 B.0.0020 hr“1 […]

A 25.0 mL sample of 0.400 M NH3(aq) is titrated with 0.400 M HCl(aq). What is the pH at the equivalence point? (Kb of NH3 = 1.8 10“5) A.2.72 B.4.97 C.7.00 D.9.03 E.11.28 Non-ideal behavior for a gas is most […]

For which of the following molecules and ions does the central atom have sp2 hybridization? (The central atom is listed first in each formula below.) A.SO4 2″ B.CO2 C.NOBr D.SBr2 E.N2O Identify from the following list of molecules and ions […]

What is the equilibrium partial pressure of water vapor above a mixture of 37.5 g H2O and 62.5 g HOCH2CH2OH at 55 C. The partial pressure of pure water at 55.0 C is 118.0 mm Hg. Assume ideal behavior for […]

What is the product of the addition of HBr to 1-hexene? A.butane B.2-bromohexane C.1-bromohexane D.1,2-dibromohexane E.1,2-dibromohexene Atomic number is the________ in the nucleus of an atom. A.number of electrons B.number of protons C.number of protons minus the number of neutrons […]

Which of the following statements concerning structural isomers is/are correct? 1/ Structural isomers have the same elemental composition, but the atoms are linked in different ways. 2/ Structural isomers have identical physical properties, but different chemical properties. 3/ Structural isomers […]

Use the following thermodynamic data. Species DfH (kJ/mol) S (J/Kmol) Fe(s) 0.0 27.8 O2(g) 0.0 205.1 Fe3O4(s) “1118.4 146.4 to calculate DS (universe) for the formation of Fe2O3(s) at 298.15 K. 3 Fe(s) + 2 O2(g) Fe3O4(s) A.”3404 J/K B.”1162 […]

Thermodynamics can be used to determine all of the following EXCEPT A.the temperature at which a reaction is spontaneous. B.the extent to which a reaction occurs. C.the direction in which a reaction is spontaneous. D.the rate of reaction. E.the entropy […]

Which of the following nonpolar molecules has the highest boiling point? A.N2 B.C2H4 C.F2 D.O2 E.CS2 What particle(s) are produced in the following reaction? A. B. C. D. E. Answer: E. Answer: E. All of the following molecules or ions […]

Nitric acid decomposes slowly in sunlight with nitrogen dioxide and oxygen as reduction and oxidation products, respectively. Write a balanced chemical equation for this reaction. A.HNO3(aq) NO2(g) + 1/2 O2(g) B.HNO3(aq) NO2(g) + 1/2 O2(g) + H+(aq) C.2 HNO3(aq) 2 […]

For a metals that crystallizes in face-centered cubic unit cell, what percentage of the space in the cell is occupied by the metal atoms? A.47% B.52% C.68% D.74% E.87% A(n) ____ is a colloidal dispersion of a solid in a […]

List all the intermolecular forces present in pure acetone. A.hydrogen bonding only B.dipole-dipole force only C.dipole-dipole force and induced dipole/induced dipole force D.hydrogen bonding and induced dipole/induced dipole force E.hydrogen bonding, dipole-dipole force, and induced dipole/induced dipole force All of […]

Which of the following types of radiation will pass through a piece of paper, but will be stopped by 0.5 cm of lead? A.a B.b C. D.g E.All of the above will pass through 0.5 cm of lead. What volume […]

If an ionic compound with the formula MX forms a primitive cubic unit cell with the anions (Xn“) at the lattice points, the cations (M2n+) will occupy A.all of the tetrahedral holes in each unit cell. B.half of the tetrahedral […]

How many joules are equivalent to 450 calories? A.0.45 J B.4.5 102 J C.9.3 10“3 J D.1.9 103 J E.4.5 105 J Which of the following statements concerning sodium and potassium is/are CORRECT? 1/ The sodium concentration in seawater is […]

What is the oxidation number of each atom in sodium hydrogen carbonate, NaHCO3? A.Na = +1, H = “1, C = +6, O = “2 B.Na = +1, H = +1, C = +4, O = “2 C.Na = +1, […]

If 77.5 g of ethylene glycol (HOCH2CH2OH) is added to 422.5 g of water, what is the mole fraction of ethylene glycol? A.0.00296 B.0.0506 C.0.183 D.0.949 E.2.96 The reaction of elemental chlorine with potassium iodide yields elemental iodine and potassium […]

You can identify a metal by carefully determining its density. A 29.51 g sample of an unknown metal is 1.50 cm long, 2.50 cm wide, and 1.00 cm thick. What is a possible identity of the element? A.nickel, 8.90 g/cm3 […]

Two students independently determine the volume of water delivered by a 10.00-mL pipet. Each student takes 8 measurements, then computes the average volume delivered and the standard deviation. The results are tabulated below. Average St. Dev. Student A 10.4 mL […]

Assuming the following reaction proceeds in the forward direction, Fe3+(aq) + Co(s) Fe2+(aq) + Co2+(aq) A.Fe3+(aq) is oxidized and Co(s) is reduced. B.Fe3+(aq) is oxidized and Co2+(aq) is reduced. C.Co(s) is oxidized and Fe3+(aq) is reduced. D.Co(s) is oxidized and […]

In an octahedral complex, electrons in and orbitals experience a greater repulsion from the lone pairs of electrons on ligands because these orbitals A.contain more electrons than the other three d orbitals. B.each contain one unpaired electron. C.are oriented directly […]

Calculate for the electrochemical cell below, Ag(s) | AgCl(s) | Cl“(aq) || Cu2+(aq) | Cu(s) given the following standard reduction potentials. Cu2+(aq) + 2 e“ Cu(s) E = +0.337 V AgCl(s) + e“ Ag(s) + Cl“(aq) E = +0.222 V […]

Which of the following regions of the electromagnetic spectrum has the lowest frequency? A.x-ray B.gamma ray C.ultraviolet D.infrared E.visible What is the freezing point of a solution containing 2.80 grams benzene (molar mass = 78.11 g/mol) dissolved in 43.0 grams […]

For which one of the following elements is the second ionization energy over ten times larger than its first ionization energy? A.B B.N C.Li D.Ne E.Cu What nucleus is produced if thorium-225 decays by electron capture? A. B. C. D. […]

What is the correct formula for potassium dihydrogen phosphate? A.KH2PO4 B.K2HPO4 C.K2H2PO4 D.K3H2PO4 E.KH2P Calculate DrG for the reaction below at 25.0 C. P4O10(s) + 6 H2O( ) 4 H3PO4( ) Species DfH (kJ/mol) S (J/K mol) P4O10(s) “2984.0 228.9 […]

As defined by Ludwig Boltzmann, the third law of thermodynamics states that A.there is no disorder in a perfect crystal at 0 K. B.in a spontaneous process, the entropy of the universe increases. C.the total entropy of the universe is […]

How many lone pairs of electrons are assigned to the carbon atom in carbon dioxide? A.0 B.1 C.2 D.3 E.4 What is the pH of a solution that results from adding 150.0 mL of 0.200 M HCl to 150.0 mL […]

Butane, C4H10, reacts with excess oxygen to produce carbon dioxide gas and water. What volume of CO2, measured at 25.0 C and 0.922 atm is produced from the reaction of 14.0 g C4H10 with excess oxygen? (R = 0.08206 Latm/molK) […]

What is the mass of 0.50 mol chromium(III) sulfide? A.2.5 10“3 g B.5.9 10“3 g C.42 g D.1.0 102 g E.110 g Which one of the following sets of ions are listed in order of lowest to highest hydration energy? […]

Use VSEPR theory to predict the electron-pair geometry and the molecular geometry of sulfur dioxide, SO2. A.The electron-pair geometry is trigonal-planar, the molecular geometry is trigonal-planar. B.The electron-pair geometry is trigonal-planar, the molecular geometry is bent. C.The electron-pair geometry is […]

A 7.3648 g sample of an oxide of mercury, when heated in a stream of hydrogen, produces Hg( ) and 0.6126 g H2O. What is formula for the compound? A.Hg2O B.HgO C.Hg2O3 D.Hg2O5 E.HgO2 What is the correct number of […]

What is the name of the following compound? A.3,4-diethyl-5-methylheptane B.3,4,5-heptane C.3-ethyl-5-(2-butyl)hexane D.3-(2-butyl)-3-ethylhexane E.3,5,6-trimethylheptane For which of the following transitions would a hydrogen atom absorb a photon with the longest wavelength? A.n = 1 to n = 2 B.n = 4 […]

The volume of a carbon atom is 1.9 10“30 m3. What is the radius of the atom in picometers? The volume of a sphere is (4/3)pr3. A.77 pm B.520 pm C.770 pm D.3.0 102 pm E.52 pm For the combustion […]

Which molecule in the reaction below is the oxidizing agent? 2 C2H6(g) + 7 O2(g) 4 CO2(g) + 6 H2O(g) A.C2H6 B.O2 C.H2O D.CO2 E.None What is the pH of a buffer that results when 0.50 mole of H3PO4 is […]

What is the pH of 0.010 M aqueous hypochlorous acid? (Ka of HOCl = 3.5 10“8) A.2.00 B.4.50 C.4.73 D.6.54 E.7.45 A statement of the first law of thermodynamics is that A.in a spontaneous process, the entropy of the universe […]