Matter and Measurement
Mrs. Alvarez
9/2013
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Definition: Mass per unit volume of a
substance
Formula: D = m/V ; units: g/mL, g/cm3,
kg/L
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Sample Problem A piece of copper has a mass of 57.54 g.
It is 9.36 cm long, 7.23 cm wide, and 0.95 mm thick.
Calculate density (g/cm3).
Strategy
 1. Get dimensions in common units.
m = 57.54 g
L = 9.36 cm
W = 7.23 cm
Thickness (Height) = 0.95 mm = 0.095 cm
 2.
Calculate volume in cubic centimeters.
V = LxWxH = (9.36 cm)(7.23 cm)(0.095 cm) =
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3. Calculate the density. D = m/V
sig figs
Be sure to check
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2. Use of density as a conversion factor:
Sample Problem: Mercury (Hg) has a density of 13.6 g/cm3.
What is the mass of 95 mL of Hg in grams? In pounds?
First, note that 1 cm3 = 1 mL
 Strategy
1.Use density as a conversion factor to calculate mass (g)
from volume.
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2.Convert mass (g) to mass (lb)
Need to know conversion factor; 454 g = 1 lb
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Density of water changes with temperature –
why?
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Intensive property - is a physical property of
matter that does not depend on the system
size or the amount of material in the system
 Examples: density, color hardness, melting point,
boiling point
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Extensive property – any property that
depends on the size of the system. A
property that changes as the amount of
matter changes.
 Examples: mass, volume, temperature, energy
released/absorbed
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State of matter: gas, liquid, solid
Kinetic Molecular Theory: A theory of the
behavior of matter at the molecular level
Kinetic Energy: The energy of a moving
object, dependent on its mass and velocity
 K.E. = 1/2mv2
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Matter has both
Macroscopic –measurable and observable to
the naked eye
 Macroscopic properties - color, length
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Submicroscopic or particulate –not
measurable with a microscope
 Particle size, chemical bond length
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3 examples
2 forms of energy
Is energy a form of matter
Symbolic level
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Measurement System – in summer work
◦ Length base unit – meter
 Conversions: 2.54 cm = 1 inch
◦ Mass base unit – kilogram
 Conversions: 453.5 g = 1 pound (only on earth!)
◦ Time base unit – second
 Conversions: 1 hour = 60 minutes;
 1 minute= 60 seconds (NOTE THESE ARE EXACT
NUMBERS)
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We did this - you tell me!
◦ Volume –
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A problem solving method –
◦ Example: how many seconds in a day ??
◦ 1 day 24 hours
1 day
60 min
1 hour
60 sec =
1 min
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Find the surface area of a room 20 feet by 12
feet in square meters. ( Use 2.54 cm = 1 inch)
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Using density as a conversion – What is the
mass of a gold cube with 2 inch sides?
(density of gold =19.3 g/cm3)
Hint: need volume in cubic centimeters -
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Accurate – close to the true value
Precision – reproducibility of the
measurement
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Percent Error:
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State the problem
◦ Organize the information
◦ Determine what you know & what you need to know
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Determine the strategy
◦ May stem from prior knowledge
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Write down each step
◦ NO WORK NO CREDIT!!
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Check your answer
◦ Is it reasonable????
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Chapter 1
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Density p. 39 # 21, 23, 25, 55, 57
Unit Conversions p. 40 31, 33, 35, 37, 53, 59
Problem solving p. 40 45, 47, 49, 61, 63, 77
Dimensional Analysis Worksheets
Sig fig review worksheet