DECEMBER 6_2007 REVIEW CLASS

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DECEMBER 6_2007 REVIEW CLASS ALL QUESTIONS FROM
CHRISTMAS ASSIGNMENT.
6) If the atom has an atomic number of 11
(given), it has 11 protons and a nuclear charge
of 11, choice 1
7) The atomic number is always the number of
protons alone, the answer is 35 as the question
mentioned 35 protons.choice
11) Most small atoms have at least one neutron
per proton. Sodium has 11 protons and thus must
have at least 11 neutrons. The best choice is 4,
mass 23 (11 protons and 12 neutrons)
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14) Cobalt-58 has an atomic number of
27(periodic table or table S) and a mass number
of 58. Subtract the mass number from the atomic
number any you get 31 neutrons. Choice 1 has 27
protons and 31 neutrons
15) 12C and 14C both have the same atomic (6)
number as they are the same element. 12C has 6
neutrons and 6 protons, 14C has 6 protons and 8
neutrons choice 3 states that 14C has more
neutrons.
17) Eliminate choices 1 and 4 because C does not
have a mass number anywhere near 35. Choice 2 is
incorrect as it would give a weighted average of
exactly 36. The correct choice is 3, closest to
35 which is the most heavily weighted mass number.
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18) Choice 3, multiply each isotopes mass number
by its percentage /100. Add the result for all
the isotopes.
21) According to the periodic table , the
electron configuration of Al is 2-8-3. The second
shell has 8 electrons, which is more than the 2
in shell one and the 3 in shell 2.
23) The third energy level (shell, principle
quantum ) can hold a maximum of 18 electrons
(2n2) , 2(3)2 equals 18.
27) Choice three is the only one in which an
inner shell is not filled. The 2-7-1 is the
excited state of the ground 2-8.
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29) The excited state of N must 1) Have
exactly 7 electrons.(atomic 7 7 electrons
neutral atom) 2) Have a configuration with an
inner shell with fewer electrons than ground.
Choice 2 (2-4-1) has only 4 second shell
electrons, the ground has (2-5 from periodic
table) --- the ground state does not have the
electron in the third shell. Choice 2 also has
the 7 electrons of neutral nitrogen. Choice 3 has
8 electrons and thus is not neutral nitrogen.
Choice 4 has only 6 electrons and choice one is
the ground state.
33) Emission occurs during fallback from an
outer energy level or sublevel to an inner energy
level (or sublevel). In this case the electron
falls from the 2p down to the inner 1s and
releases energy (emission spectra)
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38) Metals are good conductors, have metallic
luster, malleability and are on the left of the
metalloid line on the periodic table. Non metals
are poor conductors, are brittle and do not show
luster. Br is described by the later situation.
Also you must remember Br is a liquid at STP.
45) Metals are atoms from the left of the
metalloid line of the periodic table, Au is such
an element.
45 Choice 4, all are in the same group (2). Be
careful as they skip some of the elements to
throw you!
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53) Non-lustrous brittle solids are nonmetals.
Group 16 has nonmetals with six valence (outer
shell ) electrons.Choice 4 (either O or S or Se).
NOT Te(metalloid).
57) P2O5 has subscripts that cannot be reduced,
indicating that they are the in the simple
(empirical) ratio. All of the others can be
reduced and are not empirical.
62) The mole ratio of CuSO4 to H2O is 15
therefore CuSO4 1 0.250
X 5(0.250) 1.25 mol (choice A) H2O
5 X
63) (NH4)2HPO4 H9, N2, O4, P1 mole(s)
8 1 9 moles H

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64) Because ozone has a molar mass of 48 and
oxygen has an atomic mass of 16, the formula of
ozone must be O3,therefore there are 3 moles of
oxygen.
66) The molar mass of LiF is

26 g/mol
Li 1 x 7g/mol
F 1 x 19g/mol
MOLES MASS/MOLAR MASS
MOLES 39/26 1.5 mol LiF
68) Assume a 100 gram sample, convert to
grams. Convert each to moles and divide by
smallest mole quantity. S 40g/32g/mol 1,25
mol / 1.25 1 mol S O 60g/16g/mol 3.75 mol /
1.25 3 mol O choice 3, SO3
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71) 2Na 2H2O ? 2NaOH H2 Na 2
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H2 1 X
X 2 mol H2 choice 2
GIVEN
74) 4 NH3 5 O2 ? 4 NO 6 H2O NH3 4
2 4X
12 H2O 6
X X 3mol H2O choice 3
GIVEN
78) N(g) N(g) ? N2(g) The 2 moles of N(g)
BOND to form one mole of N2 molecules, energy is
ALWAYS released when bonds (or attractions) are
formed.
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76) 2 C2H2 5 O2 ? 4 CO2 2 H2O C2H2 2
0.5 mol 2X 2.5
O2 5 X X
1.25 mol O2 choice 3 CONVERT YOUR 1.25 MOLE
OF OXYGEN INTO GRAMS, THE UNITS ASKED FOR.
MOLES MASS/MOLAR MASS
1.25 MASS/32 G/MOL
MASS 40 G OXYGEN
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77) Cu 4 HNO3 ? Cu(NO3)2 2 H2O 2 NO2 STEP
ONE, convert your given ( 32 g of Cu) to
moles. Cu 1 0.5 mol
X 1 H2O 2
X X 1 mol H2O Convert the 1
mol of water to grams, the units asked for.
MOLES MASS/MOLAR MASS
MOLES 32/63.5 g/mol 0.50 mol Cu
MOLES MASS/MOLAR MASS
1 mol H2O MASS/ 18 g/mol 18 g WATER