Chapter 3
CHM 130
GCC Chemistry
3.1 Metric System:
Quantity
length
mass
volume
time
Basic Unit
meter
gram
liter
second
Symbol
m
g
L
s
Metric prefixes make the basic unit
larger or smaller.
Know the following metric prefixes!
3.2 METRIC CONVERSION FACTORS
100
1 m = ______
cm
10
1 m = ______
dm
1000
1 km = ______m
1,000,000 mm
1 m = _______
1000
1 m = _______mm
Hints = centi like 100 cents in $, deci like 10
dimes in a $, milli like millipede, micro like
microscopic (very small)
You must memorize these. Note instead of
meters, they could be liters or grams.
Fractions (Unit Factors)
• All of the preceding equalities (or unit
equations) can be put in fraction form.
Write fractions for them.
Some examples:
1 km
100 cm
1L
1,000,000u g
1000 m
1m
1000 mL
1g
10 dg
1g
1000 mm
1000 g
1g
100 cg
1m
1 kg
3.3 Metric Conversions
How many liters are in 2389 mL?
2389 mL
1L




 1000 mL 
= 2.389 L
How many kilometers are in 12,300 cm?
12,300 cm  1 m
  1 km  = 0.123 km


 100 cm   1000 m 
3.4 METRIC-ENGLISH CONVERSIONS
These conversions will be given:
1 inch = 2.54 cm
1 lb = 454 g
1 qt = 946 mL
We expect you to know 1 foot = 12 inches,
3 feet = 1 yard, 60 s = 1 min, 60 min = 1
hour, 24 hour = 1 day, etc...
Practice Probs –
Work on board and show each step
1.
2.
3.
4.
5.
How many pounds are in 248 grams?
How many inches are in 3.54 x 10-3 km?
How many kg are in 43,500 mg?
A 2.0 liter soda bottle contains how many quarts?
A dose of 5375 mL of morphine is how many liters?
1. 248 g (1 lb / 454 g) = 0.546 lbs
2. 3.54 x 10-3 km (1000 m / 1 km)(100 cm / 1 m)(1 inch / 2.54 cm) = 139 inches
3. 43,500 mg (1 g / 1000 mg)(1 kg / 1000 g) = 0.0435 kg
4. 2.0 L (1000 mL / 1 L)( 1 quart / 946 mL) = 2.1 quarts
5. 5375 mL (1 L / 1,000,000 mL) = 5.375 x 10-3 L
Watch sig fig
3.5 Three Ways to Determine Volume
1. Measured directly using graduated cylinder,
pipets, burets, etc.
2. Rectangle, cylinder, sphere can be determined
by calculation.
3. Other solids are found indirectly by liquid
displacement.
Remember 1 mL = 1 cm3 = 1 cc
VOLUME BY CALCULATION
volume = length  width  height
Calculate the volume of a shoe box measuring
24 cm by 11 cm by 16 cm.
V = (24 cm) (11 cm) (16 cm) = 4200 cm3
(2 sig fig)
3.6 VOLUME BY DISPLACEMENT
A diamond is placed in a graduated
cylinder containing 20.0 mL of water. The
volume rises to 34.7 mL. What is the
volume of the rock? Who knows what
element is in diamonds??? So what state of
matter is this element?
Carbon is Solid
V = 34.7 mL – 20.0 mL = 14.7 mL
3.7 DENSITY
density: The amount of mass per volume.
density 
density units:
g
cm
3
mass
volume
=
g
mL
=
g
cc
Think of density as how much “stuff” is in a given space.
Which state is most dense? solid
Least? gas
density air = 0.00129 g/cm3
density water = 1.00 g/cm3
density gold = 18.9 g/cm3
Sink or Float
Note how some objects float on water (a cork),
but others sink (a penny). That's because
objects that have a higher density than a liquid
will sink in the liquid, but those with a lower
density than the liquid will float. Since water's
density is about 1.00 g/cm3, a cork's density
must be (< or >) than 1.00 g/cm3, and a
penny's density must be (< or >) 1.00 g/cm3.
Cork <
Penny >
Matching
Ice cube (d=0.917 g/cm3) S1
honey (d=1.50 g/cm3)
L2
S3
iron cube (7.87 g/cm3)
L1
hexane (d=0.65 g/cm3)
rubber cube (d=1.19 g/cm3)S2
DENSITY CALCULATIONS
Use density as a conversion factor (fraction)!
Ex: Give 2 ratios for the density of chloroform.
(d = 1.48 g/mL)
1.48 g
mL
mL
and
1.48 g
Ex: How many grams would 17.5 mL of
chloroform mass? 17.5 mL (1.48 g/mL) = 25.9 g
Ex: How many mL would 0.0735 grams of
chloroform occupy? 0.0735 g (mL / 1.48g) = 0.0497 mL
3.8 TEMPERATURE
Temperature: Measure of atoms’ energy.
fast
• Hot molecules move _______
and have
_______
high energy.
slow and have
• Cold molecules move ______
_______
energy.
low
• Temperature is measured with a
thermometer.
• Check this out! (slide the Temp control)
3 scales: Fahrenheit (°F); Celsius (°C)
& Kelvin (K)
Zero Kelvin is the lowest possible
temperature where molecules stop moving;
called absolute zero. So there is no such thing
as negative Kelvins.
Temperature Conversionsthese are provided on exams
C =
(  F - 32)
1.8
 F = (  C  1.8) + 32
K = ˚C + 273
Ex: Phoenix can get up to 115oF. What
is this in Celsius and Kelvin?
46 Celsius and 319 Kelvin
HEAT
Heat: Measures total energy of all atoms.
1. Which of these two beakers has the higher
temperature? Why? Same! Both at 100
2. Which has the greater amount of heat? Why?
Second, more
water, more
molecules
moving, more
energy, more
heat
Heat Transfer
• Heat transfers from higher temperatures to
lower
• Heat transfers from hot to cold!
Consider holding a hot cookie straight
from the oven.
What loses heat? Cookie
What gains heat? Hand
A piece of metal is placed in the freezer. The
metal is then put in a bucket of hot water.
• Does the temperature of the metal increase,
decrease, or stay the same? Explain.
Temperature of metal increases as it gains heat
• Does the temperature of the water in the bucket
increase, decrease, or stay the same? Explain.
Temperature of water decreases as it loses heat
Heat transfers FROM water TO metal.
Exam I Coming Soon
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•
•
•
Study online NOTES
Study online worksheets
Study self-test Text problems
Practice conversion, density, and temperature
problems
• Know sig fig rules!!!
• Don’t forget to turn in your homework if any
Review probs if time
• How many meters per second is 95 miles per
hour? Given: 5280 feet = 1 mile and 2.54
cm = 1 inch (don’t go from miles to km)
• Martin’s head is 19 inches around. How
many mm is this?
• Dr. Kim’s famous vodka punch has a density
of 1.15 g/mL. How many mL is 24.5 grams?
• If Heather drank 445 mL of punch, how many
cups is this? Given 946 mL = 1 qt. Is she
going to be sick???
Chapter 3 Self-Test page 73
• Try # 1, 2, 4-8, 10-13
• Answers in Appendix J
• You should really try these on your own.
Work them out BEFORE looking at the
answers!!!