Transcript
6
Review for the Final Exam
CHEM-1412 2016 SU-II
Chapter 18:
25. A plot of the number of neutrons versus the number of protons in nuclei shows a narrow band of stable isotopes. By what method(s) can isotopes with a low proton-neutron ratio (i.e., ones that fall below the band of stability) decay to form elements that are more stable?
a. positron emission or electron capture.
b. positron emission or neutron capture.
c. beta emission or electron capture.
d. gamma ray emission or beta emission.
e. neutron capture or alpha emission.
ANS: A
26. Which of the following reactions is an example of alpha particle emission?
a.
b.
c.
d.
e.
ANS: E
27. How long does it take for 105 mg of tritium, , to decay to 35.0 mg? The half-life of tritium is 12.3 yr.
a. 12.3 yr
b. 14.2 yr
c. 19.5 yr
d. 24.6 yr
e. 36.9 yr
ANS: C
28. decays by alpha emission. The isotope's half-life is 2.4 ´ 104 yr. How many alpha particles are emitted per second by 1.0 ´ 10-4 mol .
a. 9.2 ´ 10-13 s-1
b. 3.0 ´ 10-9 s-1
c. 5.5 ´ 107 s-1
d. 7.6 ´ 1011 s-1
e. 4.8 ´ 1016 s-1
ANS: C
29. The rate constant for the decay of copper-62 is 9.8 minutes-1. What is the half-life of this isotope?
a. 0.071 m. b. 1.6 m. c. 14 m. d. 0.10 m. e. 9.8 m.
ANS: A
30. All of the following statements concerning radiocarbon dating are true EXCEPT
a. radiocarbon dating is used to determine the age of meteorites.
b. the decay of is used for radiocarbon dating.
c. radioactive carbon is produced by the reaction of cosmic radiation and nitrogen-14.
d. radioactive carbon decays into a nitrogen-14 atom and a beta particle.
e. radiocarbon dating is limited to objects less than 50,000 years old.
ANS: A
31. A 1.00 g sample of carbon taken from a fossilized plant has an activity of 0.19 atoms/s. What mass of is present? The decay constant of is 3.8 ´ 10-12 s-1.
a. 4.6 ´ 10-34 g
b. 5.0 ´ 10-14 g
c. 1.2 ´ 10-12 g
d. 6.1 ´ 10-12 g
e. 3.2 ´ 10-11 g
ANS: C
32. The energy change for a nuclear reaction can be calculated from which of the following equations?
a.
b. DE = hv
c. DE = cDm2
d. DE = c2Dm
e.
ANS: D
33. The point of maximum stability in the binding energy curve occurs in the vicinity of which one of the following isotopes?
a.
b.
c.
d.
e.
ANS: B
34. Calculate the energy released (per mole of deuterium consumed) for the following fusion reaction,
given the following molar masses of nucleons and nuclei. (c = 2.998 ´ 108 m/s)
particle mass (g/mol)
proton 1.007825
neutron 1.008665
deuterium 2.0140
tritium 3.01605
helium-4 4.00260
a. 5.63 ´ 103 kJ/mol
b. 1.69 ´ 1012 kJ/mol
c. 4.62 ´ 1010 kJ/mol
d. 8.44 ´ 108 kJ/mol
e. 1.69 ´ 109 kJ/mol
ANS: E
35. Marie Curie was the first person in history to
a. discover radioactivity.
b. die from leukemia.
c. win two Nobel Prizes.
d. name an element.
e. discover the neutron.
ANS: C
Chapter 22
____ 31. Saturated hydrocarbons are also known as
a. methanes.
b. alkanes.
c. alkynes.
d. alkenes.
e. ketones.
____ 32. What are the approximate bond angles between the carbon and hydrogen atoms in C3H8?
a. 60°
b. 90°
c. 109.5°
d. 120°
e. 90° and 120°
____ 33. Which of the following alkanes will have the lowest boiling point?
a.
b.
c.
d.
e. All the above alkanes have the same boiling point.
____ 34. What is the name of the following compound?
a. pentanol
b. cyclopentane
c. cyclohexane
d. cyclopentene
e. 1,5-pentane
____ 35. How many p bonds are present in (the noncyclic hydrocarbon) C3H4?
a. 0
b. 1
c. 2
d. 3
e. 6
____ 36. Formulas for derivatives of hydrocarbons may be written as R-X, where R is a hydrocarbon lacking a hydrogen atom and X is a functional group. Which of the following formulas represents a ketone?
a. ROH
b. ROR'
c. RCOR'
d. RCO2R'
e. RCHO
____ 37. Classify the following molecule according to its functional group.
a. alcohol
b. aldehyde
c. carboxylic acid
d. ether
e. ketone
____ 38. Which one of the following statements concerning isomers is INCORRECT?
a. Pairs of nonsuperimposable molecules are called enantiomers.
b. Enantiomers have identical melting and boiling points.
c. Molecules with two or more geometric isomers are termed chiral pairs.
d. Optical isomers rotate polarized light in opposite directions.
e. Structural isomers have the same composition, but the atoms are linked in different ways.
____ 39. Which of the following is an elimination reaction?
a. C2H2(g) + H2(g) ® C2H4(g)
b. CH3CH2CH2OH(l) ® CH3CHCH2(g) + H2O(l)
c. C3H6(g) + HCl(g) ® C3H7Cl(l)
d. CH3OH(aq) + HCOOH(aq) ® C2H5-O-CHO(l) + H2O(l)
e. 2C2H2(g) + 5O2(g) ® 4CO2(g) + 2H2O(g)
____ 40. Alkenes undergo addition reactions with halogens. What is the product of the reaction of propylene, C3H6, with Br2?
a.
d.
b.
e.
c.
Answer Key for Chapter 22
31. ANS: B
32. ANS: C
33. ANS: A
34. ANS: B
35. ANS: C
36. ANS: C
37. ANS: B
38. ANS: C
39. ANS: B
40. ANS: C
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