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INTRODUCTION CHAPTER QUIZ # 2 STUDY GUIDE
1) Know how to solve density problems. Be able to use your knowledge of density to
predict how things will happen in the real world.
2) Atomic theory: Be able to calculate the correct numbers of subatomic particles in an atom
from the periodic table of elements, be able to calculate mass, charge, and explain why
atomic mass on the periodic table is a decimal and not a whole number.
3) Be able to tell the difference between elements, compounds, and mixtures.
4) Be able to explain how energy affects the atoms and molecules in a substance, and how
the movement of the molecules brings about phase changes.
Density problems
1. What is the density of CO gas if 0.196 g occupies a volume of 100 ml?
2. A block of wood 3 cm on each side has a mass of 27 g. What is the density of the
block? (Hint, don’t forget to find the volume of the wood.)
3. An irregularly shaped stone was lowered into a graduated cylinder holding a volume of
water equal to 2 ml. The height of the water rose to 7 ml. If the mass of the stone was 25
g, what was its density?
4. A 10.0 cm3 sample of copper has a mass of 89.6 g. What is the density of copper?
5. Silver has a density of 10.5 grams/cm3 and gold has a density of
19.3 g/cm3. Which would have the greater mass, 5cm3 of silver or 5cm3 of gold?
6. If an object 1is more dense than object 2, which object would float on the other object?
7. Use your periodic table to answer fill out the chart, and answer the following
questions:
Element
symbol
Atomic #
B
Cr
K
Li 2+
Atomic
Mass
Number of
Protons
11
15
24
Number of
Neutrons
Number of
Electrons
6
17
24
24
39
3
9
4
8. When an atom has a charge, which particle changes number? __________________
9. If an atom has a 2+ charge, it means that it has 2 more _______________________
than ______________ .
10. Explain why atomic masses in the periodic table are not whole numbers.
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11. How can you tell the difference between an element and a compound?
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12. How can you tell the difference between a substance and a mixture?
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13. Describe how energy changes and the molecules react during a phase change.
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