Hw1_New.wpd
09/27/10
CHM 2045
FIRST PROBLEM SET
INSTRUCTOR: DON SWIETER
OFFICE: K–223
PHONE: 395–5303
MATH REVIEW and SIGNIFICANT FIGURE QUESTIONS
1.
Perform the indicated algebra: (For help see the appendices in your text.)
a.
a
× a =
b.
a
÷ a
=
c.
a =
d.
a
=
m
n
(m+3)
(2m+2)
0
–2
e.
Since a
=
, what does a
= ?
¼
1/n
2.
How many significant figures are in each of the following?
a.
9 baseballs
b.
90 baseballs
c.
9,000,000 baseballs
d.
3 dozen ostrich eggs
e.
0.1 cm
f.
100.10 cm
g.
1.01 in.
h.
0.005 g
i.
0.00500 g
3.
Rewrite the values in problem 2 ei in suitable scientific notation.
4.
Do the indicated arithmetic paying strict attention to significant figures and units.
5.
Perform the following calculations and report the answer to the proper number of significant figures
(without the aid of a calculator):
–2
2
6.
Perform the following SI conversions making proper use of unit conversion analysis:
a.
971 mg = kg
b.
82 s = ms
c.
12.3 cm = mm
2
2
d.
0.213 L = cm
e.
6.50 m
= cm
f.
7.61 kg/L = mg/mL
3
–1
–1
7.
You are given 1000 equal sized gem stones with a total mass of exactly 3 g.
These gems are valued
at $1000 per oz. (Note: 1.00 oz = 28.35 g)
Answer the following using unit – factor analysis.
a.
How much money are you out if you lose 50 stones?
b.
If you now receive an additional handful of these gems, how would you determine the value of
this handful by weighing?
Tell exactly how you would go about it.
c.
Could you determine the value of this handful by a counting procedure? What assumption would
the counting procedure depend upon?
8.
A circular cheese pizza with a 10" diameter sells for $5.00. The same pizza with a 14" diameter sells
for $10.00. Which is the better buy?
(Remember: area of a circle =
ð
r )
2
9.
Medium thinrind grapefruit (diam. = 2.0") sell for 10¢ each.
Large thinrind grapefruit
(diam. = 3.0") sell for 20¢ each.
Consider the fruit to be spherical.
Which is the better buy?
(Remember: volume of a sphere = 4/3
ð
r )
3
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QUESTIONS ON MATTER and ENERGY
10.
What are the general properties of metals and where are they found in the periodic table?
11.
What are the general properties of nonmetals and where are they found in the periodic table?
12.
Characterize each of the following as a physical or chemical process:
h.
dissolving an AlkaSeltzer in water
i.
silver tarnishing in air
2
13.
Suppose I define a new temperature scale (Hokie, °H) where the freezing point of H
O is –40°H and
2
the boiling point of H O is 320°H.
To what temperature in °C does 100°H correspond?
From a significant figure standpoint, which
scale the °H or the °C more precisely defines the temperature?
Why?
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 Fall '11
 WEINSTEIN
 Atom, pH, Mass, Atomic mass unit

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