1. A 19.0-g sample of lithium is completely burned in air to form lithium oxide. The mass of lithium
oxide must be
A) less than 19.0 g.
B) greater than 19.0 g.
C) equal to 19.0 g.
D) all of the above.
E) none of the above.
____ 2. Express the result of the following calculation in scientific...
Quiz 1
____ 1. A 19.0-g sample of lithium is completely burned in air to form lithium oxide. The mass of lithium
oxide must be
A) less than 19.0 g.
B) greater than 19.0 g.
C) equal to 19.0 g.
D) all of the above.
E) none of the above.
____ 2. Express the result of the following calculation in scientific notation: 0.0263 cm2 ÷ 88.2 cm
A)
B)
C)
D)
E)
____ 3. Calculate the mass of gold that occupies the same volume as 62.9 g of cobalt. The density of
cobalt is 8.90 g/cm3 and the density of gold is 19.30 g/cm3.
A) 2.73 g
B) 136 g
C) 1.08 104 g
D) 0.0345 g
E) 0.366 g
____ 4. An atom that has the same number of neutrons as is
A) .
B) .
C) .
D) .
E) .
____ 5. What is the symbol of the nuclide having 15 protons and 16 neutrons?
A)
B)
C)
D)
E)
____ 6. Naturally occurring element X exists in three isotopic forms: X-28 (27.977 amu, 92.21%
abundance), X-29 (28.976 amu, 4.70% abundance), and X-30 (29.974 amu, 3.09% abundance).
Calculate the atomic mass of X.
A) 29.09 amu
, B) 28.09 amu
C) 35.29 amu
D) 86.93 amu
E) 25.80 amu
____ 7. The formula of magnesium sulfide is
A) MgS.
B) MgSO2.
C) MgSO4.
D) MgSO3.
E) Mg(SO4)2.
____ 8. The formula of water, H2O, suggests
A) there is twice as much mass of hydrogen as oxygen in each molecule.
B) there are two oxygen atoms and one hydrogen atom per water molecule.
C) there is twice as much mass of oxygen as of hydrogen in each molecule.
D) there are two hydrogen atoms and one oxygen atom per water molecule.
E) none of these
____ 9. What is the best answer to report for ?
A) 2.252 g/mL
B) 2.2518 g/mL
C) 2.3 g/mL
D) 2.25 g/mL
E) 2.25183 g/mL
____ 10. The mass spectrum of an element with two naturally occurring isotopes is shown below. What is
the best estimate of the element’s atomic mass?
A) 10 amu
B) 11 amu
C) 10.8 amu
D) 10.2 amu
E) 10.5 amu
, Quiz 2
____ 1. The fully hydrated form of sodium sulfate is the decahydrate, Na2SO4 • 10H2O. When heated
the hydrated salt loses water. How many water molecules are found per formula unit in a
partially dehydrated sample of sodium sulfate with a formula mass of 160.1 amu (i.e. find n for
Na2SO4 • nH2O)?
A) 1 waters.
B) 5 waters.
C) 3 waters.
D) 4 waters.
E) 7 waters.
____ 2. What is the mass of oxygen atoms in 0.305 mol Fe(CO)5?
A) 17.0 g
B) 59.7 g
C) 24.4 g
D) 4.88 g
E) 18.3 g
____ 3. How many moles of iron atoms are contained in 4.39 g of iron?
A) 245 mol
B) 0.0579 mol
C) 0.0786 mol
D) 0.122 mol
E) 0.169 mol
____ 4. How many molecules are there in 2.80 kg of hydrazine, N2H4?
A) 8.75 1023
B) 5.27 1025
C) 1.88 1022
D) 2.80 1026
E) 4.65 1021
____ 5. What is the mass percentage of carbon in the compound C6H6O2?
A) 5.5 %
B) 70.9 %
C) 65.5 %
D) 29.1 %
E) 14.3 %
____ 6. Analysis of a compound showed that it contained 76.0 % fluorine atoms and 24.0 % carbon
atoms by mass. What is its empirical formula?
A) CF2
B) C2F3
C) CF3
D) C2F5
E) CF
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