CHEM 1332 Chp. 16, 17, & 18
At 437. K, ΔGo equals -43.3 kJ for the reaction, 2 Cl(g) ⇌ Cl2(g). Calculate the value of ln(K) for the reaction at this temperature.
1.19E1 ± 2%
Given the following data, Ca(s) + CO2(g) + ½ O2(g) ⇌ CaCO3(s), ΔGo = -733. 2 Ca(s) + O2(g) ⇌ 2 CaO(s), ΔGo = -1,204. Find ΔGo for CaCO3(s) ⇌ CaO(s) + CO2 (g).
131 ± 2 Like Hess's Law but using Gibbs free energy. Here we'll flip the first equation so its 733 Then we'll divide the second reaction by 2, so overall it'll be. (733) + (-1204/2) = 131
Assuming that the octet rule is not violated, what is the formal charge on Br in the molecule below?HBrO3 (connectivity = HOBrO2) 0 +1 +2 +3 -3 none of these is correct
+2
Given the values of ΔGfo given below in kJ/mol, calculate the value of ΔGo in kJ for the combustion of ammonia to forms nitrogen dioxide and water vapor. (Use the lowest possible integers when balancing the equation). ΔGfo (NO2) = 59. ΔGfo (H2O(g)) = -229. ΔGfo (NH3) = -15.
+8228.0 J/K
A voltaic cell consists of an Ni/Ni2+ half-cell and a Co/Co2+ half-cell. The standard reduction potential for Ni2+ is -0.247V and for Co2+ is -0.277 V. Calculate Ecell at 25 ºC when the concentration of [Ni2+] = 3.59 x 10-6 M and [Co2+]= 9.41 x 10-2 M.
-0.101 ± 0.02
Determine Eo for the following reaction, using the given standard reduction potentials:Cr3+(aq) + Co(s) → Cr2+(aq) + Co2+(aq)Eo for Co2+(aq) = -0.28 VEo for Cr3+(aq) = -0.41 V
-0.13
Determine Eo for the following reaction, using the given standard reduction potentials:Sn(s) + Co2+(aq) → Sn2+(aq) + Co(s)Eo for Co2+(aq) = -0.28 VEo for Sn2+(aq) = -0.14 V
-0.14
In thionyl chloride, Cl2SO (S is the central atom), the formal charge on oxygen and number of lone pairs on oxygen are, respectively, (assume all the atoms obey the octet rule): +1 and one -1 and one 0 and one +2 and one -1 and three none of these answers is correct
-1 and three
Given the values of ΔGfo given below in kJ/mo, calculate the value of ΔGo in kJ for the combustion of 1 mole of ethane to form carbon dioxide and liquid water.ΔGfo (C2H6(g)) = -28.ΔGfo (CO2(g)) = -393.ΔGfo (H2O(l)) = -224.
-1,430 ± 2
At a certain temperature, 986 K, Kp for the reaction,H2(g) + Br2(g) ⇌ 2 HBr(g) is 8.08 x 105.Calculate the value of ΔGo in kJ for the reaction at 986 K.
-1.12E2 ± 2%
What is the value of ΔGo in kJ at 25 oC for the reaction between the pair: Cr(s) and Fe2+(aq) to give Fe(s) and Cr3+(aq)? Given reduction half-reactions Fe2+(aq)+2e− → Fe(s) E°= -0.44 Cr3+(aq)+3e− → Cr(s) E°= -0.74
-1.74E2 ± 2%
At a certain temperature, 766, Kp for the reaction,Cl2(g) + I2(g) ⇌ 2 ICl(g), is 9.26 x 1012.Calculate the value of ΔGo in kJ for the reaction at 766 K.
-1.90E2 ± 2% ΔG=-RTlnK same as ΔG=-RTlnKp Plug in and watch out for units.
Given the following data, H2(g) + 1/2 O2(g) ⇌ H2O(g) ΔGo = -230. 2 H(g) + O(g) ⇌ H2O(g) ΔGo = -929. 2 H(g) + 2 O(g) ⇌ H2O2(g) ΔGo = -1,075. 2 O(g) ⇌ O2(g) ΔGo = -497. H2O2(l) ⇌ H2O2(g) ΔGo = 49. Determine ΔGfo for H2O2(l).
-176 ± 2
Calculate the value of ΔGo in kJ for the combustion of 1 mole of propane (C3H8) to form carbon dioxide and gaseous water at 298 K. (value ± 2) So in J/mol K S° (C3H8(g)) = 272. S° (O2(g)) = 202. S° (CO2(g)) = 210. S° (H2O(g)) = 182. ΔHfo in kJ/mol ΔHfo (C3H8(g)) = -107. ΔHfo (CO2(g)) = -391. ΔHfo (H2O(g)) = -229.
-2,005 ± 2 Given entropy & enthalpy, we can use this equation where we solve for each variable separately. ΔGo= ΔH - TΔS ΔS°= ΣnSproduct - ΣnSreaction =(3)(210) + (4)(182) - (1)(272) + (5)(202) =76 J/mol > 0.076 kj/mol ΔH°= (3)(-391) + (4)(182) - (1)(272) + (5)(202) =-1982 Kj/mol Plug it all in.
The combustion of hydrogen in the presence of excess oxygen yields water: 2H2(g) + O2(g) → 2H2O(l) The value of ΔS° for this reaction is __________ J/K mol. *Can't insert table, refer to table provided on question. Also on Appendix 4 in the text.
-326.3 ΔS°= ΣnSproduct - ΣnSreaction ΔS°= (2)(69.91) - (2)(130.58) + (205)
The value of ΔGo for the reaction, N2(g) + 3 H2(g) ⇌ 2 NH3(g) is -32.90 kJ at 298 K. Calculate the value of ΔG in kJ at 298 K if the partial pressures of N2, H2 and NH3 are 6.84, 9.3, and 72.5 atm respectively.
-33.0 ± 2% ΔG=-RTlnK same as ΔG=-RTlnKp We have separate pressures of each, so we'll determine Kp= C^c / (A^a)(B^b) where they're raised to their coefficient. So we'll have Kp = (72.5)^2/ (9.3)^3 x (6.84)
At 1,379. K, ΔGo equals 48.5 kJ for the reaction, 2 I(g) ⇌ I2(g). Calculate the value of ln(K) for the reaction at this temperature.
-4.23E0 ± 2% ΔG=-RTlnK same as ΔG=-RTlnKp Rearrange so its lnK = -ΔG/RT Plug it all in and watch out for units.
The value of ΔGo for the precipitation reaction, Ca2+(aq) + CO32-(aq) ⇌ CaCO3(s) is −48.1 kJ at 298 K. Calculate the value of ΔG in kJ at 298 K if the concentrations are [Ca2+] = 0.993 M and[CO32−] = 0.822 M.
-47.60 ± 0.2
The value of ΔGo for the precipitation reaction, Ca2+(aq) + CO32-(aq) ⇌ CaCO3(s) is -48.1 kJ at 298 K. Calculate the value of ΔG in kJ at 298 K for the concentrations:[Ca2+]=6.36 M and [CO32−] =3.37 M.
-55.7 ± 2%
At a certain temperature, 465 K, Kp for the reaction,2 SO2(g) + O2(g) ⇌ 2 SO3(g) is 7.98 x 106.Calculate the value of ΔGo in kJ for the reaction at 465 K.
-67.8 ± 2
A particular reaction has a ΔHo value of -115. kJ and ΔSo of -134. J/mol K at 298 K. Calculate ΔGo at 299. K in kJ, assuming that ΔHo and ΔSo do not significantly change with temperature.
-74.9 ± 2 Plug into ΔGo= ΔH - TΔS Watch out for units! J > kJ
How many grams of vanadium may be formed by the passage of 4,109 C through an electrolytic cell that contains an aqueous V(V) salt.
0.433 ± 2%
How many moles of electrons are required to produce 28.9 g of lead metal from a solution of aqueous lead(IV)nitrate?
0.558 ± 5%
An atom of 85Ga has a mass of 84.957005 amu. mass of1H atom = 1.007825 amu mass of a neutron = 1.008665 amu Calculate the mass defect (deficit) in amu/atom. Ga Atomic #= 31
0.753 ± 0.001 1. Determine mass of protons and neutrons by multiplying # of protons/neutrons with given masses. i.e mass of protons (1H) = (1.007825)(31) Total calculated mass= proton mass + neutron mass 2. Determine mass deficit (Δm)= calculated mass - actual mass
An atom of 105In has a mass of 104.914558 amu. mass of1H atom = 1.007825 amu mass of a neutron = 1.008665 amu Calculate the mass defect (deficit) in amu/atom. In atomic #= 49
0.954 ± 0.001 1. Determine mass of protons and neutrons by multiplying # of protons/neutrons with given masses. protons= 49 neutrons= 56 proton (1H) mass= (1.007825 amu)(49) neutron mass= (1.008665)(56) Total calculated mass= proton mass + neutron mass 2. Determine mass deficit (Δm)= calculated mass - actual mass **Writing out the decimals can get time consuming during the test and leaves room for error during rounding. It'd best to use the calculator strategically for all calculations.
An atom of 110I has a mass of 109.935060 amu. Calculate the mass defect in amu/atom. Enter your answer with 4 significant figures and no units. Use the masses: mass of 1H atom = 1.007825 amu mass of a neutron = 1.008665 amu 1 amu = 931.5 MeV/c2
0.9735 1. Determine mass of protons and neutrons by multiplying # of protons/neutrons with given masses. Total calculated mass= proton mass + neutron mass 2. Determine mass deficit (Δm)= calculated mass - actual mass **Writing out the decimals can get time consuming during the test and leaves room for error during rounding. It'd best to use the calculator strategically for all calculations.
Which one of the following is a correct representation of a beta particle? A. 4/2 e B. 1/0 B C. 0/1 e D. 0/-1 e E. 2/4 B
0/-1 e refer to table
An atom of 132Sn has a mass of 131.917760 amu. mass of1H atom = 1.007825 amu mass of a neutron = 1.008665 amu Calculate the binding energy in MeV per atom. 1 amu = 931.5 MeV/c2 Sn atomic # = 50
1,103 ± 1 1. Determine mass of protons and neutrons by multiplying # of protons/neutrons with given masses. Total calculated mass= proton mass + neutron mass 2. Determine mass deficit (Δm)= calculated mass - actual mass 3. Convert to MeV
An atom of 135I has a mass of 134.910023 amu. Calculate the binding energy in MeV per atom. Enter your answer with 4 significant figures and no units. Use the masses: mass of 1H atom = 1.007825 amu mass of a neutron = 1.008665 amu 1 amu = 931.5 MeV/c2
1,131 1 Determine Δm then convert to MeV using 931.5 MeV.
How many grams of gold may be formed by the passage of 75.6 amps for 2.4 hours through an electrolytic cell that contains a molten Au(I) salt.
1,333 ± 2%
What is the value of the equilibrium constant, K, at 25 oC for the reaction between the pair: Cl2(g) and Br-(aq) ? Reduction Half-reactions Cl2(l)+2e− → 2Cl− (aq) E°= +1.36 Br2(l)+2e− → 2Br−(aq) E°= +1.09
1.360000000E9 ± 20%
itromethane, CH3NO2, has the connectivity shown below (you will need to complete the Lewis dot structure to answer the question). Due to resonance, what is the average N-O bond order? 0.5 1.0 1.5 1.25 none of these is correct
1.5
Consider the reaction between ozone and a metal cation, M2+, to form the metal oxide, MO2, and dioxygen:O3 + M2+(aq) + H2O(l) →O2(g) + MO2(s) + 2 H+for which Eocell = 0.44.Given that Eored of ozone is 2.07 V, what is the value of Eored of MO2?
1.63 ± 0.01
A voltaic cell consists of an Mn/Mn2+ half-cell and a Pb/Pb2+ half-cell. Calculate [Pb2+] when Ecell is 1.04 V and [Mn2+] = 0.375 M. Use reduction potential values of Mn2+ = −1.18 V and for Pb2+ = −0.13 V.
1.72E-1 ± 5%
What is the value of ΔGo in kJ at 25 oC for the reaction between the pair: Ag(s) and Ni2+(aq) to give Ni(s) and Ag+(aq)? Reduction Half-reactions Ag+(aq)+e− → Ag(s) E°= +0.80 Ni2+(aq)+2e− → Ni(s) E°= -0.23
1.99E2 ± 2%
What is the value of the equilibrium constant, K, at 25 oC for the reaction between the pair: I2(s) and Br−(aq) ? Given reduction half-reactions I2(l) + 2e− → 2I−(aq) E°= +0.54 Br2(l)+2e− → 2Br−(aq) E°= +1.09
2.49E-19 ± 20%
A particular reaction has a ΔHo value of -107. kJ and ΔGo of -124. kJ at 590. K.Calculate ΔSo at 590. K in J/K.
28.8 ± 2
How many equivalent resonance structures can be drawn for the molecule of SO3 without having to violate the octet rule on the sulfur atom? 5 2 1 4 3
3
A particular reaction has a ΔHo value of -195. kJ and ΔSo of -333. J/mol K at 298 K. Assuming that ΔHo and ΔSo do not significantly change with temperature, determine the temperature in Celsius (°C) at which the spontaneity of this reaction changes.
312 ± 2 To determine minimum for a reaction to be spontaneous, it'll have a ΔGo< or = 0, so we'll set ΔGo = 0. Convert any units and rearrange ΔGo= ΔH - TΔS to T = ΔH/ΔS
Given the following data: 2 Fe(s) + 3/2 O2(g) ⇌ Fe2O3(s), ΔGo = -745. CO(g) + ½ O2 ⇌ CO2(g), ΔGo = -247. Find ΔGo for Fe2O3(s) + 3 CO(g) ⇌ 2 Fe(s) + 3 CO2(g).
4 ± 2
An atom of 65Ga has a mass of 64.932735 amu. mass of1H atom = 1.007825 amu mass of a neutron = 1.008665 amu Calculate the binding energy in kilojoules per mole. 1 amu = 931.5 MeV/c2 c = 2.99792 x 10^8 m/s 1 amu = 1.6605 x 10^-27 kg
5.4300000000E10 ± 1% 1. Determine mass deficit (amu) 2. Convert amu > kg using 1.6605 x 10^-27 kg 0.6093 amu x 1.6605 x 10^-27 = 1.012 x 10^-27 kg 3. convert kg > J/nuclide using c = 2.99792 x 10^8 m/s **Make sure to raise it to ^2, because ΔE (J/nuclide) = Δm ∗ c^2. (1.012 x 10^-27) x (2.99792 x 10^8)^2 = 9.093 x 10^-11 J/nuclide 4. Convert J/nuclide > J/mol be multiplying it with 6.022 x 10^23 9.093 x 10^-11 x 6.022 x 10^23 = 5.47 x 10 ^13 J/mol 5. Convert J/mol > kj/mol 5.47 x 10 ^13 / 1000 = 5.47 x 10^10 kJ/mol *1 kj = 1000 J
An atom of 113I has a mass of 112.923650 amu. Calculate the binding energy in MeV per NUCLEON. Enter your answer with 3 significant figures and no units. Use the masses: mass of 1H atom = 1.007825 amu mass of a neutron = 1.008665 amu 1 amu = 931.5 MeV/c2
8.33 1. Calculate Δm then to MeV using 931.5 MeV 2. Determine MeV per nucleon by dividing answer by given mass (113)
An atom of 65Ga has a mass of 64.932735 amu. mass of1H atom = 1.007825 amu mass of a neutron = 1.008665 amu Calculate the binding energy in MeV per nucleon. 1 amu = 931.5 MeV/c2 Ga Atomic #= 31
8.662 ± 0.01 1. Determine mass of protons and neutrons by multiplying # of protons/neutrons with given masses. Total calculated mass= proton mass + neutron mass 2. Determine mass deficit (Δm)= calculated mass - actual mass 3. Convert to MeV 4. Divide answer by given mass # (65, not the exact mass). This is because we're doing this per nucleon, which is a combination of both neutrons and protons.
An atom of 110I has a mass of 109.935060 amu. Calculate its binding energy per MOLE in kJ. Enter your answer in exponential format (1.23E4) with 3 significant figures and no units. Use the masses: mass of 1H atom = 1.007825 amu mass of a neutron = 1.008665 amu 1 amu = 931.5 MeV/c2 c = 2.99792 x 10^8 m/s
87,600,000,000 5.4300000000E10 ± 1% 1. Determine mass deficit (amu) 2. Convert amu > kg using 1.6605 x 10^-27 kg 3. convert kg > J/nuclide using c = 2.99792 x 10^8 m/s **Make sure to raise it to ^2, because ΔE (J/nuclide) = Δm ∗ c^2. 4. Convert J/nuclide > J/mol by multiplying it with 6.022 x 10^23 9.093 x 10^-11 x 6.022 x 10^23 = J/mol 5. Convert J/mol > kj/mol by dividing by 1000 *1 kj = 1000 J
At 486 K., ΔGo equals -39.2 kJ for the reaction, 2 SO2(g) + O2(g) ⇌ 2 SO3(g). Calculate the value of ln(K) for the reaction at this temperature.
9.7E0 ± 2%
The number of neutrons in is 55/26 Fe +2 A.26 B23 C.29 D.53 E.55
C. 29 26 = protons 55= protons + neutrons neutrons = 55-26 = 29
Given the values of ΔGfo given below in kJ/mol, calculate the value of ΔGo in kJ for the reaction: NH4Cl(s) → HCl(g) + NH3(g) ΔGfo (NH4Cl) = -203. ΔGfo (HCl(g)) = -93. ΔGfo (NH3) = -19.
91 ± 2 Similar to when we found the entropy of a reaction. ΔGo=ΣnGproduct - ΣnGreaction ΔGo=(1)(-93) + (1)(-19) - (1)(-203)
Balance the following equation in basic solution using the lowest possible integers and give the coefficient of hydroxide ion.P4(aq) → H2PO2-(aq) + PH3(g) A.3 B.2 C.1 D.0 E.4
A. 3
Balance the following equation in acidic solution using the lowest possible integers and give the coefficient of H+.P4(aq) → HPO32-(aq) + PH3(g) A.4 B.10 C.8 D.6 E.12
A. 4
161Tl is expected to be stable. A.False B.True
A. False
122Sb is expected to be stable. A.True B.False
A. True
Which of the following nuclides would be expected to be particularly stable? A.calcium-40 B.potassium-38 C.argon-39 D.chlorine-37
A. calcium-40
Which of the following statement(s) is/are correct? i) Breeder reactors convert the non-fissionable nuclide, 238U to a fissionable product. ii) The control rods in nuclear fission reactors are composed of a substance that emits neutrons. iii) Electric power is widely generated using nuclear fusion reactors. A.i) only B.ii) only C.iii) only D.i) and ii) only E.i) and iii) only F.ii) and iii) only G.i), ii) and iii) H.None of the choices are correct.
A. i) only i) A Breeder Reactor is a nuclear reactor that "breeds" fuel. A Breeder consumes fissile and fertile material at the same time as it creates new fissile material. Production of fissile material in a reactor occurs by neutron irradiation of fertile material, particularly Uranium-238 and Thorium-232. ii) A control rod is used to absorb neutrons so that the nuclear chain reaction taking place within the reactor core can be slowed down. They help control the reaction. iii) Electricity is most often generated at a power plant by electromechanical generators, primarily driven by heat engines fueled by combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind. Other energy sources include solar photovoltaics and geothermal power.
In the electrolysis of molten FeBr2, which product forms at the anode? A.Br2(g) B.H2(g) C.Fe(l) D.O2(g)
A. Br2(g)
The half-life of a radionuclide A.is constant. B.gets shorter with passing time. C.gets longer with passing time. D.gets shorter with increased temperature. E.gets longer with increased temperature.
A. is constant.
Balance the following equation in acidic solution: Zn(s) + NO2-(aq) → Zn2+(aq) + N2(g) What is the coefficient of water? A.1 B.2 C.4 D.6 E.8
C. 4
In the Lewis dot structure for phosphoric acid, H3PO4, phosphorus and the oxygen without a hydrogen have formal charge of ___ and ___, respectively. Assume that the octet rule is not violated. A.0, 0 B.+1, -1 C.+5, -1 D.+3, -2 E.-1, 0
B. +1, -1 OH . . . . .| . .. OH-P - O : . . . . |. . .. . . . . OH Determine lewis dot structure that obeys octet rule. So we can't use a structure where P is double bonded to O (that's the other conformation). Formal charge = V e- - (shared e- /2 ) - unshared e- for P: 5 - (8/2) - 0 = +1 for O: 6 - (2/2) -6 = -1
The half-life of carbon-11 is 20.3 minutes. How much of a 100.0 mg sample remains after 1.50 hours? A.8.48 mg B.4.63 mg C.12.9 mg D.22.6 mg E.7.70 mg
B. 4.63 mg ln(N/No)=-kt What is k? t(1/2)= 0.693 / k Solve for k 20.3 = 0.693/k k= 0.034 Plug in and solve for N (remaining amount).
The reaction below is spontaneous under standard conditions - true or false? Br2(l) + Mn2+(aq) → MnO4-(aq) + Br-(g) (in acidic solution)Use the fact that the reduction potential for MnO4-(aq) is +1.51 V and for Br2(l) it is +1.065 V. A.True B.False
B. False
209Bi is expected to be stable. A.False B.True
B. True
Hydrogen can be prepared by suitable electrolysis of aqueous strontium salts A.False B.True
B. True
Among these types of nucleons (odd and even numbers), which has the fewest stable nuclides? A.odd number of protons and even number of neutrons B.odd number of protons and odd number of neutrons C.even number of protons and even number of neutrons D.even number of protons and odd number of neutrons E.Odd or even numbers of nucleons does not influence the stability of nuclides
B. odd number of protons and odd number of neutrons
In the electrolysis of molten CoCl3, which product forms at the anode? A.O2(g) B.Cl2(g) C.H2(g) D.Co(l)
B. Cl2(g)
Potassium metal can be prepared by electrolysis of its aqueous salts A.True B.False
B. False
A radioisotope has a neutron/proton ratio which is too low. Which of the following processes is least likely to occur for such a nucleus? A.alpha emission B.beta emission C.electron capture D.positron emission E.all the above are equally likely to occur
B. beta emission We can predict how unstable nuclides will decay: if it's heavy with p>80 - alpha decay high n/p = beta emission low n/p = electron capture & positron emission. This is most likely to occur if it was the opposite situation.
What is needed to balance the nuclear fusion reaction below? 2 1/1 H → 2/1 H+ ? A. 0/1 n B. 0/1 e C. 0/-1 e D. 1/0 n
B. 0/1 e
What nuclide is formed when 238/92 U undergoes this portion of its decay series: alpha, beta, beta, alpha, alpha, alpha? A. 226/88 Ra B. 222/86 Rn C. 230/90 Th D. 206/82 Pb
B. 222/86 Rn
Which one of the following is true? A.Some spontaneous nuclear reactions are exothermic. B.Some spontaneous nuclear reactions are endothermic. C.All spontaneous nuclear reactions are exothermic. D.There is no relationship between exothermicity and spontaneity in nuclear reactions. E.All spontaneous nuclear reactions are endothermic.
C. All spontaneous nuclear reactions are exothermic.
As the atomic number of the elements increases, the ratio of neutrons to protons in stable nuclei A.decreases B.stays the same C.increases D.decreases until iron, Fe, then increases E.increases until iron, Fe, then decreases
C. increases As the atomic number increases, the ratio of neutrons to protons increases in the stable nuclei.
If a nucleus undergoes beta particle emission A.its atomic number decreases by four and its mass number decreases by two. B.its atomic number decreases by two and its mass number decreases by four. C.its atomic number increases by one and its mass number is unchanged. D.its atomic number decreases by one and its mass number increases by one. E.its atomic number is unchanged and its mass number decreases by one.
C. its atomic number increases by one and its mass number is unchanged. It changes both atomic number by +1 and neutron number by -1
The term "nucleons" refers to the number of ________ in the atom. A.neutrons B.protons C.neutrons and protons D.neutrons, protons and electrons E.None of these
C. neutrons and protons
Which one of the following devices converts radioactive emissions to light for detection? A.Geiger counter B.photographic film C.scintillation counter D.none of these E.radiotracer
C. scintillation counter A.Geiger counter: detects/measure ionizing radiation. B.photographic film: detects radiation when exposed to ionising radiation by turning dark and opaque C.scintillation counter: produces a flash of light when ionized radiation travels a solid/liquid. E.radiotracer: A chemical compound where 1 or more atoms have been replaced by a radionuclide. Used in hospitals.
What isotope (?) is needed to balance the nuclear fission reaction below? 1/0 n + 235/92 U → 137/52 Te + ? + 2 1/0 n A. 96/40 Zr B. 79/40 Ca C. 97/40 Zr D. 80/41 Nb
C. 97/40 Zr
Consider the following half-reactions. Au+(aq) + e- → Au(s), Eo = 1.69 VN2O(g) + 2 H+(aq) + 2 e- → N2(g) + H2O(l), Eo = 1.77 VCr3+(aq) + 3 e- → Cr(s), Eo = −0.74 V Which of these is the strongest reducing agent listed here? Au+(aq) Au(s) N2O(g) N2(g) Cr3+(aq) Cr(s)
Cr(s)
Balance the following equation in basic solution using the lowest possible integers and give the coefficient of water.MnO4-(aq) + SO32-(aq) → MnO2(s) + SO42-(aq) A.4 B.2 C.3 D.1
D. 1
Balance the following equation in basic solution: NO2(g) → NO2-(aq) + NO3-(aq) What is the coefficient of water? A.8 B.4 C.2 D.1 E.6
D. 1
A rock contains 0.275 mg of lead-206 for each milligram of uranium-238. The half-life for the decay of uranium-238 to lead-206 is 4.5 x 109 yr. The rock was formed __________ yr ago. A.1.42 x 109 B.9.62 x 108 C.1.24 x 109 D.1.79 x 109 E.1.39 x 109
D. 1.79 x 109
If we start with 1.000 g of cobalt-60, 0.675 g will remain after 3.00 yr. This means that the of is __________ yr. A.3.08 B.4.44 C.2.03 D.5.30 E.7.65
D. 5.30 t(1/2) = (ln2)/k = 0.675/k Solve for k using ln(N/No)= -kt ln(0.675/1.00)=-k(3) k= 0.131 Plug it in and solve t(1/2)= 0.693/0.131=5.30
Balance the following equation in acidic solution using the lowest possible integers and give the coefficient of water.MnO4-(aq) + H2S2O3(aq) → Mn2+(aq) + HSO4-(aq) A.2 B.3 C.4 D.7 E.6
D. 7 1. Determine oxidation & reduction reactions. 2.Balance out elements (like S), use H2O to balance O and H+ to balance H. 3. Balance out the charges and multiply each half-reaction by a multiple so that the e- cancel each other out in the full redox reaction. So here we would have multiplied the redox reaction (MnO4>Mn) by x8, and the oxidation rxn (H2S2O3>HSO4) by x5. They'll have 40 e- on either side, they're balanced so we can cancel them out. 4. Write out the full reaction and subtract./cancel out any identical species on both sides on the rxn. Here notice H+ and H2O appear on both sides. Subtract 32-25 H2O= 7H2O on the right side, and 64-50 H+= 14 H+ on the left side. Full rxn> 14H+ + 8MnO4 + 5H2S2O3 > 8 Mn2+ + 7H2O + 10HSO4.
The half-life for beta decay of strontium-90 is 28.8 years. A milk sample is found to contain 10.3 ppm strontium-90. How many years would pass before the strontium-90 concentration would drop to 1.0 ppm? A.92.3 B.0.112 C.186 D.96.9 E.131
D. 96.9
By what (single step) process does osmium-185 change to rhenium-185? A.alpha emission B.beta emission C.gamma ray emision D.electron capture E.neutron capture
D. electron capture Here we see that the atomic # decreases by 1.
Which of the following statement(s) is/are correct? i) The mass defect is the difference in mass between that of a nucleus and the sum of the masses of its component nucleons. ii) The splitting of a heavier nucleus into two nuclei with smaller mass numbers is known as nuclear fission. iii) The first example of nuclear fission involved bombarding 235/92 U with 4/2 He nuclei. A.i) only B.ii) only C.iii) only D.i) and ii) only E.i) and iii) only F.ii) and iii) only G.i), ii) and iii) H.None of the choices are correct.
D. i) and ii) only ii) the other possibility is fusion, where 2 light nuclei come together to make 1 heavy stable nuclei. iii) Incorrect, 235?92 U was first bombarded with 1/0 neutron to make a unstable isotope which would undergo fission.
Which of the following statement(s) is/are correct? i) Breeder reactors convert the non-fissionable nuclide, 238U to a fissionable product. ii) The most stable nucleus in terms of binding energy per nucleon is 56Fe. iii) Electric power is widely generated using nuclear fusion reactors. A.i) only B.ii) only C.iii) only D.i) and ii) only E.i) and iii) only F.ii) and iii) only G.i), ii) and iii) H.None of the choices are correct.
D. i) and ii) only I don't know why ii is true it should be false if I understand correctly. i) A Breeder Reactor is a nuclear reactor that "breeds" fuel. A Breeder consumes fissile and fertile material at the same time as it creates new fissile material. Production of fissile material in a reactor occurs by neutron irradiation of fertile material, particularly Uranium-238 and Thorium-232. ii) Nickel-62 is an isotope of nickel having 28 protons and 34 neutrons. It is a stable isotope, with the highest binding energy per nucleon of any known nuclide (8.7945 MeV). Binding energy is energy required to decompose the nucleus into it components. The higher the binding energy=more stable. iii) Electricity is most often generated at a power plant by electromechanical generators, primarily driven by heat engines fueled by combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind. Other energy sources include solar photovoltaics and geothermal power. BUT if it was nuclear fission to produce electricity in nuclear reactions, that is correct.
Which of the following nuclides is most likely to undergo beta decay? A. 190/80 Hg B. 195/80 Hg C. 200/80 Hg D. 205/80 Hg
D. 205/80 Hg
A freshly prepared sample of curium-243 undergoes 3312 disintegrations per second. After 6.00 yr, the activity of the sample declines to 2755 disintegrations per second. The half-life of curium 243 is ___ yrs. A.4.99 B.32.6 C.7.21 D.0.765 E.22.6
E. 22.6 ln(N/No)=-kt Solve for k and plus into t(1/2) = 0.693 /k
Balance the following equation in basic solution using the lowest possible integers and give the coefficient of water.AlH4-(aq) + H2CO(s) → Al3+ (aq) + CH3OH(aq) A.0 B.3 C.1 D.2 E.4
E. 4
Silicon-28 reacts with hydrogen-2 to produce phosphorus-29 and what particle? A.a proton B.an alpha particle C.a beta particle D.a positron E.a neutron
E. a neutron When balancing nuclear reactions, check their mass (shown here) and their atomic numbers (not shown). A. proton = 1/1 p adds 1 to mass and atomic # B. alpha particles add 4/2 C. beta particles add 0/1 D. Positron add 0/1, this we could add if the just the atomic number needed to be balanced. E. neutron is 1/0, adding 1 to the atomic mass.
If a nucleus decays by successive alpha, beta and beta particle emissions, its atomic number will A.decrease by four. B.decrease by two. C.increase by four. D.increase by two. E.be unchanged.
E. be unchanged.
If a nucleus gains a neutron and then undergoes beta emission, A.its atomic number decreases by one and its mass number increases by one. B.its atomic number is unchanged and its mass number increases by one. C.both its atomic number and its mass number are unchanged. D.its atomic number increases by one and its mass number is unchanged. E.its atomic number increases by one and its mass number increases by one.
E. its atomic number increases by one and its mass number increases by one. Recall, beta emission increases atomic # +1 and # neutrons by -1. Adding +1 to the atomic # increases the mass by 1, and the neutron that was added is lost so we can not count it.
What nucleus decays by successive β, β, α emissions to produce uranium-236? A.232/88 Ra B.230/80 Ra C.240/92 Pu D.242/94 Pu E.240/92 U
E.240/92 U 236/92 U is what we ended up with, work backwards. α add +4 to the mass and -1 to atomic number (the opposite). β will -1 twice, so -2 overall. So we see the mass go from 236 > 240 and the atomic # change from: 92 > 94 > 93 > 92
1 mole of NO2(g) has a greater entropy than 1 mole of N2O4(g). True or false
False
For the combustion of acetylene at 298.15 K, 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g) calculate ΔS°(universe) given ΔS°(system) = -194.6 J/K and ΔH°(system) = -2511.2 kJ. -2453.2 J/K -186.2 J/K +186.2 J/K +1290.4 J/K +8228.0 J/K
False
The process of a radioactive nucleus decay is spontaneous. True or False? False True
False
Answer this question without using numbers from the book (or anywhere else!) ΔS for the following reaction is positive. True or false? O2(g, V = 1.0 L, P = 1 atm) → O2(g, V = 0.1 L, P = 10 atm) True False
False entropy = ΔS, an increase (positive value) in entropy occurs when there's an increase in disorder. Here we see a decrease in volume and increase in temperature. We're limiting the space for molecules to move, and that decreases disorder = negative change in value for ΔS.
Co-55 undergoes positron decay. What is the product nucleus? Enter your answer using the same format, i.e, symbol-mass number
Fe-55 0/1 p is added symbol looks like 0/1 B
Co-56 undergoes positron decay. What is the product nucleus? Enter your answer using the same format, i.e, symbol-mass number
Fe-56
Which of the following statement(s) is/are correct? i) The energy change, , when ( 15.99491461956 amu) is formed from 8 protons and 8 neutrons is less than zero. ii) Nuclear fission is used to produce electric power in nuclear reactors iii) The first example of nuclear fission involved bombarding with neutrons. A.i) only B.ii) only C.iii) only D.i) and ii) only E.i) and iii) only F.ii) and iii) only G.i), ii) and iii) H.None of the choices are correct.
H. None of the choices are correct.
Consider the following half-reactions. Au+(aq) + e- → Au(s), Eo = 1.69 V N2O(g) + 2 H+(aq) + 2 e- → N2(g) + H2O(l), Eo = 1.77 V Cr3+(aq) + 3 e- → Cr(s), Eo = -0.74 V Which substance is the strongest oxidizing agent? Au+(aq) Au(s) N2O(g) N2(g) Cr3+(aq) Cr(s)
N2O(g)
Rb-89 undergoes beta decay. What is the product nucleus? Enter your answer using the same format, i.e, symbol-mass number
Sr-89 beta decay changes the: +1 atomic # & -1 neutron #
A particular reaction has a ΔHo value of -133. kJ and ΔSo of -151. J/mol K at 298 K. Calculate ΔGo at 432. K in kJ, assuming that ΔHo and ΔSo do not significantly change with temperature.
True
The process of sodium metal reacting with water to form sodium hydroxide and hydrogen gas is spontaneous. True or False? False True
True
ΔS for the following process is positive. True or false? A solid explosive converting to a gas False True
True
The process of alcohol burning in air is spontaneous. True or False? True False
True Combustion reactions are always spontaneous.
Consider the Figure shown in which X represent Zn(s), T represents Co(s), and S is a solution that is 1.0 M in Co2+. The reduction potentials of Co2+ and Zn2+ are -0.27 V and -0.76 V, respectively. At which electrode does reduction occur? Y Z X S T
X
What product(s) forms at the cathode in the electrolysis of an aqueous solution of ZnI2? A.Iodine B.H2 and OH- C.Zn D.O2 and H+
Zn
Identify the oxidizing agent and the reducing agent in the reaction.NO3-(aq) + 4Zn(s) + 7OH-(aq) + 6H2O(l) → 4Zn(OH)42-(aq) + NH3(aq) oxidizing agent: OH-; reducing agent: NO3- oxidizing agent: Zn; reducing agent: NO3- oxidizing agent: NO3- ; reducing agent: Zn oxidizing agent: Zn ; reducing agent: OH-
oxidizing agent: NO3- ; reducing agent: Zn