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Chapter 3 Sample


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
Dalton incorporated the law of conservation of mass into his atomic theory by asserting that
a.
atoms are indivisible.
b.
atoms of different elements have different properties.
c.
matter is composed of atoms.
d.
atoms can be destroyed in chemical reactions.
 

 2. 
If 4.0 g of element A combine with 10. g of element B, then 12 g of element A combine with ____ g of element B.
a.
10.
c.
24
b.
12
d.
30.
 

 3. 
If two or more compounds are composed of the same two elements, the ratio of the masses of one element that combine with a fixed mass of the other element is a simple whole number. This is a statement of the law of
a.
conservation of mass.
c.
multiple proportions.
b.
mass action.
d.
definite composition.
 

 4. 
Oxygen can combine with carbon to form two compounds, carbon monoxide and carbon dioxide. The ratio of the masses of oxygen that combine with a given mass of carbon is 1:2. This is an example of
a.
the law of conservation of mass.
c.
the law of conservation of energy.
b.
Dalton's atomic theory.
d.
the law of multiple proportions.
 

 5. 
If 63.5 g of copper (Cu) combine with 16 g of oxygen (O) to form the compound CuO, how many grams of oxygen will be needed to combine with the same amount of copper to form the compound CuO2?
a.
16 g
c.
64 g
b.
32 g
d.
127 g
 

 6. 
According to Dalton's atomic theory, atoms
a.
are destroyed in chemical reactions.
b.
can be divided.
c.
of each element are identical in size, mass, and other properties.
d.
of different elements cannot combine.
 

 7. 
The atomic theory proposed by Dalton has been
a.
totally discarded.
c.
accepted unchanged to the present day.
b.
expanded and modified.
d.
found to be plagiarized.
 

 8. 
Experiments with cathode rays led to the discovery of the
a.
proton.
c.
neutron.
b.
nucleus.
d.
electron.
 

 9. 
Because any element used in the cathode produced electrons, scientists concluded that
a.
all atoms contained electrons.
c.
atoms were indivisible.
b.
only metals contained electrons.
d.
atoms carried a negative charge.
 

 10. 
Because most particles fired at metal foil passed straight through, Rutherford concluded that
a.
atoms were mostly empty space.
c.
electrons formed the nucleus.
b.
atoms contained no charged particles.
d.
atoms were indivisible.
 

 11. 
Rutherford's experiments led him to conclude that atoms contain massive central regions that have
a.
a positive charge.
c.
no charge.
b.
a negative charge.
d.
both protons and electrons.
 

 12. 
Nuclear forces exists because the particles in the nucleus are
a.
oppositely charged.
c.
highly energized.
b.
close together.
d.
moving very fast.
 

 13. 
The most common form of hydrogen has
a.
no neutrons.
c.
two neutrons.
b.
one neutron.
d.
three neutrons.
 

 14. 
The tritium atom consists of
a.
one proton, two neutrons, and two electrons.
b.
one proton, one neutron, and one electron.
c.
one proton, two neutrons, and one electron.
d.
two protons, one neutron, and one electron.
 

 15. 
All isotopes of hydrogen contain
a.
one neutron.
c.
one proton.
b.
two electrons.
d.
two nuclei.
 

 16. 
As the atomic number increases, the number of electrons in a neutral atom
a.
decreases.
c.
remains the same.
b.
increases.
d.
is undetermined.
 

 17. 
In determining the atomic mass of elements, the standard is the
a.
C-12 atom.
c.
H-1 atom.
b.
C-14 atom.
d.
O-16 atom.
 

 18. 
The relative atomic mass of an atom can be found by comparing the mass of the atom to the mass of
a.
one atom of carbon-12.
c.
a proton.
b.
one atom of hydrogen-1.
d.
uranium-235.
 

 19. 
The average atomic mass of an element is the average of the atomic masses of its
a.
naturally occurring isotopes.
c.
radioactive isotopes.
b.
two most abundant isotopes.
d.
artificial isotopes.
 

 20. 
The average atomic mass of an element
a.
is the mass of the most abundant isotope.
b.
may not equal the mass of any of its isotopes.
c.
cannot be calculated.
d.
always adds up to 100.
 

 21. 
The atomic mass of an element listed in the periodic table is the
a.
average atomic mass.
b.
relative atomic mass of the most abundant isotope.
c.
relative atomic mass of the most abundant radioactive isotope.
d.
mass number of the least abundant isotope.
 

 22. 
The number of atoms in 1 mol of carbon is
a.
6.022 ´ 1022.
c.
5.022 ´ 1022.
b.
6.022 ´ 1023.
d.
5.022 ´ 1023.
 

 23. 
Molar mass
a.
is the mass in grams of one mole of a substance.
b.
is numerically equal to the average atomic mass of the element.
c.
Both (a) and (b)
d.
Neither (a) nor (b)
 

 24. 
The mass of a sample containing 3.5 mol of silicon atoms (atomic mass 28.0855 amu) is approximately
a.
28 g.
c.
72 g.
b.
35 g.
d.
98 g.
 

 25. 
The mass of 5.000 mol of cesium (atomic mass 132.9 amu) is
a.
664.5 g.
c.
6.022 ´ 1023 g.
b.
132.9 g.
d.
5.000 g.
 



 
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