Download Atoms, Molecules and Ions

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Section: _____________
Chapter 2 Homework:
Atoms, Molecules, and Ions
1.
Briefly define the following:
a. Law of Conservation of Mass
b. Law of Definite Proportions
c. Dalton’s Atomic Theory
d. Law of Multiple Proportions
2.
Describe the contribution made by the following scientists:
a. Priestley
b. Thomson
c. Millikan
d. Rutherford
3. Fill in the table below:
Symbol
Atomic Number
1
Mass Number
Number of Neutrons
1H
8
63
17
80
119
35
36
Cu
Chapter 2 Worksheet
v.08 Steward
page 1
Name: _________________________
Section: _____________
4. How many gold-197 atoms are in a 0.156 gram sample? (Watch sig figs in your answer!)
5. Classify the following as a mixture or pure substance, and atom, molecule, or compound.
a
b
c
d
e
f
g
h
i
j
k
l
6. Describe the difference between ionic and covalent compounds.
7.
CH4
Circle the substances that are ionic in the list below:
LiCl
Chapter 2 Worksheet
v.08 Steward
C2H4
NaNO3
CoCl2
CO2
KBr
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Name: _________________________
Section: _____________
8. Calculate the atomic weight for the element lithium. Lithium-6 has an natural percent
abundance of 7.5% and an atomic mass of 6.015122 amu. Lithium-7 has a natural abundance
of 92.5% and an atomic mass of 7.016003 amu.
9. What is the difference between atomic mass and molar mass? Molecular mass and molar
mass?
10. If a C-12 atom has an atomic mass of 12 amu (exactly) and a molar mass of 12 g (exactly),
how many grams are in 1 amu?
11. What is the difference between an element’s atomic mass number and atomic mass?
12. Which has a higher number of atoms, a 20.00g sample of carbon atoms or a 20.00g sample of
N atoms.
13. How many atoms of He has the same mass as 1.00x1012 carbon atoms? How many atoms of
Al has this same mass?
Chapter 2 Worksheet
v.08 Steward
page 3