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UNIVERSITY OF DUBLIN
TRINITY COLLEGE
FACULTY OF SCIENCE
Department of Chemistry
Junior FreshmanHilary Term, 2004
Multiple Choice Test 1
Monday 12th JanuaryExam Hall and Goldsmith Hall 12.00 – 13.00
Answer All questions
A Periodic Table giving Atomic Weights etc., and a Table of fundamental constants is attached.
INSTRUCTIONS
1.Using a soft pencil (grade B or softer) complete sections A, B, C and D on the Computer Answer Form. Write your student number in Section Das wellas marking the number on the form by filling in the box with a clear thick horizontal line (not a , X or 0).
GOOD BAD BAD BAD BAD
2.Answer each question by first marking on the question paper the answer that you think is appropriate. Do not mark more than one answer to eachquestion. In questions with numerical answers, mark the answer closest to yours, if you do not get exactly any of those given.
3.Carefully transfer your answers to the Computer Answer Form. If you make a mistake, rub it out with a CLEAN eraser and enter the correctanswer. Use only a soft pencil and mark your answers with a clear thick horizontal line. Failure to do this could result in the misreading of your form. Do notwrite comments on the form.
4.When you have finished, make sure your name, student number and seat number are on the Computer Answer Form and hand it up to the invigilator. Do not in any way tear, crumple or deface the form. This form is the only record of your answers.
5.There will be no negative marking for this exam.
1.Which of the following statements is incorrect ?
(a)The mass number is equal to the sum of the number of protons and neutrons in an atom.
(b)Isotopes of the same element have the same atomic number but different mass numbers.
(c)The elements in the Periodic Table are listed in order of increasing atomic number.
(d)The molar mass is the mass in grams of one mole of a substance.
(e)Elements in the same Group of the Periodic Table have the same electronic configuration.
Correct answer (e)
2.Lactic acid (C3H6O3) is responsible for the sour taste in out-of-date milk.
57.04 mL of 0.098 M NaOH is required to neturalise 50.0 mL of a lactic acid solution.
C3H6O3 + NaOH H2O + C3H5O3Na
What is the molarity of the lactic acid solution?
(a)0.098 M
(b)0.112 M
(c)0.224 M
(d)0.056 M
(e)1.000 M
Correct answer (b)
3.Balance the equation below for the reaction of acid with a solution of MnO42. How many moles of MnO42 are used to form 1 mole of MnO2 in the balanced equation?
MnO42 + H+ MnO4 + MnO2 + H2O
(a)one mole
(b)two moles
(c)three moles
(d)four moles
(e)five moles.
Correct answer (c)
4.Which of the following statements are correct ?
(i)The oxidation number of Mn in MnO4 is V
(ii)Lithium has an atomic number of three
(iii)The molar mass of Ca3(PO4)2 is 100 gmol1
(iv)The reaction of BaCl2 with Na2SO4 is an example of a precipitation reaction
(v)The mass percentage of carbon in CaCO3 is 12%
(a)i, ii and iii only
(b)i and ii only
(c)ii and v only
(d)ii, iv and v only
(e)iii, iv and v only
Correct answer (d)
5.For ideal gases which of the following statements are incorrect?
- At constant temperature, the volume of a fixed mass of gas is inversely proportional to its pressure.
- At constant temperature and pressure the volume of 1 mole of any gas is always 22.4L
- Equal masses of any gas have the same number of molecules
- At constant pressure and temperature, 1L of O2 reacts with 2L of CO to form 2L of CO2.
(a)(ii) and (iii) only
(b)(i), (ii) and (iv) only
(c)(i) and (iii) only
(d)(iii) and (iv) only
(e)(ii) only.
Correct answer (a)
6.Given the following thermochemical data:
Hof (NO) = +90.0 kJ mol-1; 2CO(g) + O2 (g) 2CO2(g) Horxn = -560.0 kJ
Calculate the standard enthalpy change for: CO(g) + NO (g) CO2(g) + ½ N2(g)
(a)–325 kJ
(b)–370 kJ
(c)–450 kJ
(d)–505 kJ
(e)–550 kJ
Correct answer (b)
7.H for the transformation
grey tin white tin
is 2.09 kJ mol-1 and S is 7.31 J mol-1 K-1. What temperature range favours the formation of grey tin.
(a)Above 286 K
(b) Below 286 K
(c)Above 572 K
(d)Below 572 K
(e)Above 304 K
Correct answer (b)
8.Consider a process during which water freezes in a cold container to form ice. Which of the following statements correctly describes the changes that occur during this process ?
(a)The free-energy of the system decreases, the entropy of the system increases and the enthalpy of the system increases.
(b)The free-energy of the system decreases, the entropy of the system increases and the enthalpy of the system decreases.
(c)The free-energy of the system decreases, the entropy of the system decreases and the enthalpy of the system decreases.
(d)The free-energy of the system increases, the entropy of the system increases and the enthalpy of the system increases.
(e)The free-energy of the system increases, the entropy of the system decreases and the enthalpy of the system decreases.
Correct answer (c)
9.A C60 ‘buckyball’ weighing 1.1956 1021 grams travels at one tenth the velocity of light. What is its de Broglie wavelength?
(a)1.848 1017 m
(b)1.848 1012 m
(c)1.848 10+1 m
(d)1.848 10+10 m
(e)1.848 10+20 m
Correct answer (a)
10.The electron in a hydrogen atom falls from the 4th to the 2nd shell. The emitted light has:
(a)a wavelength 4.862 1010 m
(b)a wavelength 9.843 109 m
(c)a frequency 6.1661 1018 Hz
(d)an energy 4.0856 1021 J
(e)an energy 246.06 kJ mol1
Correct answer (e)
- The Ni2+ ion:
(a)has four unpaired electrons
(b)has five unpaired electrons
(c)has eight electrons in its outer shell
(d)has electron spin ½
(e)is non-magnetic.
Correct answer (c)
- The ionization energy of the oxygen atom is less than that of the nitrogen atom because:
(a)the 2p orbital has higher energy than the 2s
(b)there is greater repulsion in the 2p subshell of O than in the 2p of N
(c)Hund’s Rule requires maximum electron spin in the N atom
(d)O has greater nuclear charge than N
(e)The O atom has a smaller ionic radius than the N atom.
Correct answer (b)
- Molecular orbital theory predicts that the F22+ ion:
(a)has a bond order of 3
(b)has zero binding energy
(c)has unpaired electrons
(d)has an empty bonding molecular orbital
(e)is non-magnetic.
Correct answer (c)
14.The complete combustion of 2.1 g of propene gives:
(a)13.20 g of CO2 and 5.40 g of H2O
(b)7.33 g of CO2 and 4.50 g of H2O
(c)5.81 g of CO2 and 3.56 g of H2O
(d)6.60 g of CO2 and 2.70 g of H2O
(e)6.60 g of CO2 and 5.40 g of H2O
Correct answer (d)
15.Cyclohexane can exist:
(a) as a chair conformer only
(b) as both boat and chair conformers
(c) as a chair conformer where all the C-H bonds are equatorial
(d)as a boat conformer only
(e) as a chair conformer where all the C-H bonds are axial.
Correct answer (b)
16.The reaction that takes place between bromine and (E)-but-2-ene is:
(a) a free radical addition reaction
(b) an acid-catalysed addition reaction
(c) an endothermic addition reaction
(d) an electrophilic addition reaction
(e) an impossible addition reaction.
Correct answer (d)
©University of Dublin 2004
Department of Chemistry
Use the following values for fundamental constants, conversion factors, atomic masses and other data for examination purposes:
Constants
Gas Constant / R = 8.314 J K1 mol1(R = 8.206 10-2 L atm K-1 mol-1)
Boltzmann’s Constant / kB = 1.381 1023 J K1
Planck’s Constant / h = 6.626 1034 J s
= h/2 = 1.055 1034 J s
Velocity of light / c = 2.998 108 m s-1
Charge of electron / e = 1.602 1019 C
Rest mass of electron / me = 9.109 1031 kg
Rest mass of proton / mp = 1.673 1027 kg
Vacuum permittivity / o = 8.854 1012 J1 C2 m1
Vacuum permeability / o = 4 107 J s2 C-2 m-1
Bohr magneton / = 9.274 1024 J T-1
Nuclear magneton / n = 5.051 1027 J T-1
Rydberg constant / R= 2.178 1018 J = 1.097 105 cm-1
Avogadro’s constant / NA = 6.022 1023 mol-1
Faraday constant / F = NAe = 9.648 104 C mol1
Bohr radius / ao = 5.292 1011 m
Molar volume at S.T.P. / Mv = 22.414 dm3 mol1
Conversion factors etc.
1 eV = 1.602 1019 J = 9.648 104 J mol1
1 cm1 = 1.986 1023 J = 11.96 J mol1 = 1.240 104 eV
1 Å = 0.1 nm = 1010 m
1 standard atmosphere = 1.013 105 N m-2 (Pa) = 760 torr = 1013 mbar
1 L = 1 dm3 = 103 m3
1 Debye (D) = 3.336 1030 C m
1 calorie = 4.184 J
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1 / The Periodic Table of the Elements / 181 /
( ) mass numbers of most stable isotope / 2
H / 2 / 13 / 14 / 15 / 16 / 17 / He
1.0079 / 4.0026
3 / 4 / 5 / 6 / 7 / 8 / 9 / 10
Li / Be / B / C / N / O / F / Ne
6.941 / 9.01218 / 10.81 / 12.011 / 14.0067 / 15.9994 / 18.9984 / 20.179
11 / 12 / 13 / 14 / 15 / 16 / 17 / 18
Na / Mg / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 10 / 11 / 12 / Al / Si / P / S / Cl / Ar
22.98977 / 24.305 / 3d, 4d, 5d / 26.9815 / 28.0855 / 30.9738 / 32.06 / 35.453 / 39.948
19 / 20 / 21 / 22 / 23 / 24 / 25 / 26 / 27 / 28 / 29 / 30 / 31 / 32 / 33 / 34 / 35 / 36
K / Ca / Sc / Ti / V / Cr / Mn / Fe / Co / Ni / Cu / Zn / Ga / Ge / As / Se / Br / Kr
39.0983 / 40.08 / 44.9559 / 47.88 / 50.9415 / 51.996 / 54.938 / 55.847 / 58.9332 / 58.69 / 63.546 / 65.38 / 69.72 / 72.59 / 74.9216 / 78.96 / 79.904 / 83.80
37 / 28 / 29 / 40 / 41 / 42 / 43 / 44 / 45 / 46 / 47 / 48 / 49 / 50 / 51 / 52 / 53 / 54
Rb / Sr / Y / Zr / Nb / Mo / Tc / Ru / Rh / Pd / Ag / Cd / In / Sn / Sb / Te / I / Xe
85.4678 / 87.62 / 88.9059 / 91.22 / 92.9064 / 95.94 / (97.9) / 101.07 / 102.9055 / 106.42 / 107.868 / 112.41 / 114.82 / 118.69 / 121.75 / 127.60 / 126.9045 / 131.29
55 / 56 / 57 / 72 / 73 / 74 / 75 / 76 / 77 / 78 / 79 / 80 / 81 / 82 / 83 / 84 / 85 / 86
Cs / Ba / #La / Hf / Ta / W / Re / Os / Ir / Pt / Au / Hg / Tl / Pb / Bi / Po / At / Rn
132.9054 / 137.33 / 138.9055 / 178.49 / 180.9479 / 183.85 / 186.207 / 190.2 / 192.22 / 195.08 / 196.9665 / 200.59 / 204.383 / 207.2 / 208.9804 / (209) / (210) / (222)
87 / 88 / 89
Fr / Ra / *Ac
(223) / 226.0254 / 227.0278
# Lanthanum series
58 / 59 / 60 / 61 / 62 / 63 / 64 / 65 / 66 / 67 / 68 / 69 / 70 / 71
Ce / Pr / Nd / Pm / Sm / Eu / Gd / Tb / Dy / Ho / Er / Tm / Yb / Lu
140.12 / 140.9077 / 144.24 / (145) / 150.36 / 151.96 / 157.25 / 158.9254 / 162.50 / 164.9304 / 167.26 / 168.9342 / 173.04 / 174.967
* Actinium series
90 / 91 / 92 / 93 / 94 / 95 / 96 / 97 / 98 / 99 / 100 / 101 / 102 / 103
Th / Pa / U / Np / Pu / Am / Cm / Bk / Cf / Es / Fm / Md / No / Lr
232.0381 / 231.0359 / 238.0389 / 237.0482 / (244) / (243) / (247) / (247) / (242.1) / (254) / (257) / (258.1) / (259.1) / (260)