CH1810 - Practice Exam #3 - Answers Name: ____________________________________________ Score: __________________________ Part I (~4 points each) Multiple Choice - Choose the best answer and place the letter corresponding to the answer in the space provided AND on the Scantron form. _____ 1. Identify the type of solid for gold. A) metallic atomic solid B) ionic solid C) nonbonding atomic solid D) molecular solid E) network atomic solid _____ 2. Identify the type of solid for argon. A) metallic atomic solid B) ionic solid C) nonbonding atomic solid D) molecular solid E) network atomic solid _____ 3. Give the coordination number for a body-centered cubic cell. A) 0 B) 6 C) 8 D) 10 E) 12 _____ 4. Name the following: [Pt(H 2 O) 4 F 2 ]Br 2 A) tetraaquadifluoroplatinum(IV) bromide B) tetraaquadibromodifluoroplatinate C) platinum(II)bromide D) platinum(III)tetraaquadifluorobromide E) platinum (II) dibromodifluorotetrahydride _____ 5. Choose the chemical formula for diaquadicarbonylzinc tetrabromopalladate (IV). A) [PdZn(H 2 O) 2 (CO) 2 ]Br 4 B) [Zn(H 2 O) 2 (CO) 2 ] 2 [PdBr 4 ] C) [Pd(H 2 O) 2 ][Zn(CO) 2 ]Br 4 D) [Pd(H 2 O) 2 ] 2 [Zn(CO) 2 ] 3 Br 4 E) [Zn(H 2 O) 2 (CO) 2 ][PdBr 4 ] A C C A E
Multiple Choice - Choose the best answer and place the letter corresponding to the answer in the space provided AND on the Scantron form.
_____ 1. Identify the type of solid for gold.
A) metallic atomic solid B) ionic solid C) nonbonding atomic solid D) molecular solid E) network atomic solid _____ 2. Identify the type of solid for argon.
A) metallic atomic solid B) ionic solid C) nonbonding atomic solid D) molecular solid E) network atomic solid
_____ 3. Give the coordination number for a body-centered cubic cell.
A) 0 B) 6 C) 8 D) 10 E) 12
_____ 4. Name the following: [Pt(H2O)4F2]Br2
A) tetraaquadifluoroplatinum(IV) bromide B) tetraaquadibromodifluoroplatinate C) platinum(II)bromide D) platinum(III)tetraaquadifluorobromide E) platinum (II) dibromodifluorotetrahydride
_____ 5. Choose the chemical formula for diaquadicarbonylzinc tetrabromopalladate (IV).
A) [PdZn(H2O)2(CO)2]Br4 B) [Zn(H2O)2(CO)2]2[PdBr4] C) [Pd(H2O)2][Zn(CO)2]Br4 D) [Pd(H2O)2]2[Zn(CO)2]3Br4 E) [Zn(H2O)2(CO)2][PdBr4]
A
C
C
A
E
_____ 6. For the following balanced equation, determine the rate of reaction with respect to [H2]. N2(g) + 3 H2(g) → 2 NH3(g) A) Rate = + B) Rate = -
C) Rate = + D) Rate = -
_____ 7. Give the characteristic of a first order reaction having only one reactant.
A) The rate of the reaction is not proportional to the concentration of the reactant. B) The rate of the reaction is proportional to the square of the concentration of the reactant. C) The rate of the reaction is proportional to the square root of the concentration of the reactant. D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant. E) The rate of the reaction is directly proportional to the concentration of the reactant
_____ 8. What is the overall order of the following reaction, given the rate law?
X + 2 Y → 4 Z Rate = k[X][Y] A) 3rd order B) 5th order C) 2nd order D) 1st order E) 6th order
_____ 9. What are the units of k in the following rate law? Rate = k[X][Y]1/2
A) M/s B) M-1s-1 C) M1/2s-1 D) M-1/2s-1
E) M-1s-1/2 _____ 10. Which of the following statements is FALSE?
A) The half life of a zero order reaction is dependent on concentration. B) The half life of a second order reaction is not dependent on concentration. C) The rate of second order reactions is dependent on concentration. D) The rate of a first order reaction is dependent on concentraion. E) None of the statements are FALSE.
E
Δ[H2]Δt
31
Δ[H2]Δt
31
Δ[H2]Δt
13
Δ[H2]Δt
13
C
D
D
B
_____ 11. The half life for the decay of radium is 1620 years. What is the rate constant for this first-order process?
A) 4.28 × 10-4 yr-1 B) 1.12 × 10-4 yr-1 C) 2.33 × 10-4 y-1 D) 8.91 × 10-4 y-1 E) 6.17 × 10-4 yr-1
_____ 12. Identify an heterogeneous catalyst.
A) CFCs with ozone B) solid Pd in H2 gas C) KI dissolved in H2O2 D) H2SO4 with concentrated HCl E) H3PO4 with an alcohol
_____ 13. Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]2
A) The rate of reaction will increase by a factor of 2. B) The rate of reaction will increase by a factor of 4. C) The rate of reaction will increase by a factor of 5. D) The rate of reaction will decrease by a factor of 2. E) The rate of reaction will remain unchanged.
_____ 14. How many half-lives are required for the concentration of reactant to decrease to 12.5% of its original value?
A) 3 B) 2 C) 2.5 D) 2.75 E) 8
_____ 15. The combustion of ethylene proceeds by the reaction
C2H4(g) + 3O2 (g) → 2CO2 (g) + 2H2O(g)
When the rate of disappearance of O2 is 0.28 M s-1, the rate of appearance of CO2 is ________ M s-1.
A) 0.19 B) 0.093 C) 0.84 D) 0.42 E) 0.56
A
B
B
A
A
_____ 16. Determine the identity of the daughter nuclide from the alpha decay of Rn. A) Po B) Ra C) Th D) Rn E) At
_____ 17. Determine the identity of the daughter nuclide from the electron capture by Fe. A) Co B) Mn C) Co D) Mn
E) Cr
______ 18. The following reaction represents what nuclear process?
Pb → e + Bi
A) beta emission B) positron emission C) gamma emission D) electron capture
______ 19. Which of the following nuclides is most likely to decay via positron emission?
A) Cs-137 B) I-131 C) Al-24 D) K-42 E) N-14
A 222 86
218 84
226 88
224 90
223 86
221 85
B 55 26
55 27
55 25
56 27
54 25
51 24
A137 82
0 -1
137 83
C
Part II (~8 points each) - Show all of your calculations for full credit.
_____ 1. Aluminum crystallizes in a face centered cubic structure with an edge length of 2√2 r. The atomic radius of aluminum is 143 pm. What is the density of aluminum
_____ 2. What is the equilibrium concentration of Co2+ in s solution that is initially 0.090 M Co(NO3)2 and 0.700 M OH- after the following equilibria is established:
_____ 3. Determine the rate law and the value of k for the following reaction using the data provided. S2O82⁻(aq) + 3 I⁻(aq) → 2 SO42⁻(g) + I3⁻(aq) [S2O82⁻]i (M) [I⁻]i (M) Initial Rate (M-1s-1) 0.30 0.42 4.54 0.44 0.42 6.65 0.44 0.21 3.33
Answer: 1.3 x 10-9 M
Answer: 2.71 g/cm3
Answer: Rate = 36 M-1s-1 [S2O82-][I-]
_____ 4. The first-order decomposition of N2O at 1000 K has a rate constant of 0.76 s-1. If the initial concentration of N2O is 10.9 M, what is the concentration of N2O after 9.6 s?
_____ 5. The first-order rearrangement of CH3NC is measured to have a rate constant of 3.61 x 10-15 s-1 at 298 K and a rate constant of 8.66 × 10-7 s-1 at 425 K. Determine the activation energy for this reaction.
_____ 6. The age of an ancient tree trunk is estimated using radiocarbon dating. If the trunk has a C-14 decay rate that is 34% of what it is in living plants, how old is the trunk? The half-life of C-14 is 5730 years.
