This chapter introduces fundamental concepts of matter including its properties and measurement. It discusses the scientific method and defines key terms like element, compound, mixture, and properties. It also covers units of measurement, accuracy and precision, significant figures, density, and using conversion factors to interconvert between units. The chapter establishes a foundation for quantitative work in chemistry.

1. Chapter 1:
Matter – Its Properties and
Measurement

2. The Scientific Method
Observation Hypothesis Experiment Established
Theory
modify modify
Experiment Theory
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3. Properties of Matter
• Matter: occupies space and displays
mass and inertia
• Composition: relative proportions of the
components of a sample of matter
ex. water is 11.19% H and 88.81% O by mass
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4. Properties of Matter
• Physical property:
– a property that can be measured or observed without
changing the matter’s composition
• Chemical property:
– a property that comes with observing a change in
chemical composition
• Extensive property: depends on the quantity of
matter present
• Intensive property: does NOT depend on the
quantity of matter present
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5. Elements and Compounds
• Element:
– cannot be decomposed into a simpler substance
through chemical processes; distinguished by the
unit of the atom
• Compound:
– a substance made from the atoms of two or more
elements bonded chemically in defined proportions
• Compounds can only be decomposed into
their respective elements via chemical
processes
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6. Pure Substances and Mixtures
• A pure substance
– A substance with a fixed and uniform composition and distinct
properties (ex: pure water)
• A mixture:
– A combination of two or more pure substances which can
vary in composition and properties
a) homogeneous: ex: salt water
b) heterogeneous: ex: oil and water
• It is possible to separate mixtures through physical
porcesses
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7. Pure Substances and Mixtures
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8. Measuring Matter
an observed measurement not followed by a unit is meaningless!
The seven base SI units are:
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9. Who cares about units anyway?
• Mars Climate Orbiter
• probe sent by NASA to Mars to
study its weather
• the $168 million probe was
destroyed in 1999 after entering
the Martian atmosphere
• desired altitude: 140-150 km
• altitude attained: 57 km
• investigation revealed that the
on board computer used SI
units, while the computers on
Earth were using BE units
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10. SI Prefixes
Value
Prefix
Symbol
1012
tera-
T
109
giga-
G
106
mega-
M
103
kilo-
k
102
hecto-
h
101
deca-
da
10-1
deci-
d
10-2
centi-
c
10-3
milli-
m
10-6
micro-
µ
10-9
nano-
n
10-12
pico-
p
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11. Mass versus Weight
• mass:
– measures the quantity of matter in an object
• weight:
– the force of gravity on an object
The kilogram (kg) is the official SI unit, but we will most often
use the gram (g):
1 kg = 1000 g
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12. Volume
• volume: the size of a
cube (i.e., m3)
• we will most often use
the litre (L) for
measuring volumes
1000 mL = 1 L
1000 L = 1 m3
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13. Temperature
• the SI unit is the kelvin (K)
• absolute zero temperature is 0 K or -273.15oC
• the freezing point of water is 273.15 K or 0oC
• the boiling point of water is 373.15 K or 100oC
always use the temperature in K in your calculations!
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14. Accuracy and Precision
• Accuracy:
– indicates how close a measured value is to
the actual (or accepted) value
• Precision:
– indicates the degree of reproducibility of a
measured quantity
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15. Accuracy and Precision
accurate not accurate,
and precise but precise
not precise, neither accurate
but accurate nor precise
• accurate measurements are usually precise, but a systematic
error will produce values which are precise but not accurate
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16. Scientific measurements
• Scientific notation: N x 10n
6.022 045 x 1023 instead of 602 204 500 000 000 000 000 000
N=6.022 045 and n=23
• Significant figures
– digits considered to be significant in the calculation or
measurement of a quantity
this balance is precise to ±0.01 kg
an object that has a mass of 6.732 kg
will give a measurement of 6.73 ± 0.01 kg
__________
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17. Rules for sig figs…
• all non zero digits are significant
4
6.732 kg has __ significant figures
• zeros between two sig figs are also significant
5
6.0061 kg has __ significant figures
• zeros to the left of a sig fig are not significant
3
0.0502 kg has __ significant figures
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18. Rules for sig figs…
• if the value is greater than 1, all zeros to the right of the
decimal point are significant
4
6.000 kg has __ significant figures
• when converting to scientific notation, it may sometimes
be ambiguous whether hanging zeros are significant or
not
4500 kg could be 4.5 x 103, 4.50 x 103, or 4.500 x 103 kg
therefore 4500 kg could have 2, 3, or 4 sig figs!
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19. Rules for sig figs
• a whole number with perfect precision has an infinite
number of significant figures
if we determine the average of 3 trials, we can assume it s
3.000 000 000 … trials
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20. Rules for sig figs…
• addition/subtraction:
– the answer must have the same number of sig figs after
the decimal as the element of the calculation with the
least number of sig figs after the decimal point
+ 0.2225
+ 2.73 + 2.06
+ 0.321 ! 1.1
3.27
rounded to ______ 1.0
rounded to ______
+ 3.2735 + 0.96
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21. Rules for sig figs…
• multiplication/division:
– the answer must have the same number of sig figs
as the element of the calculation with the least
number of sig figs
2.2 x 3.7845 = 8.32590 8.3
rounded to ______
3.76 / 4.236 = 0.8876298 0.888
rounded to ______
(2.27 x 7.324) / 3.3 = 5.0380 5.0
rounded to ______
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22. Rules for sig figs…
• Logarithms
– the answer must have the same number of sig figs as the log
element
log(957) = 2.980911... = 2.98 ??
= log(9.57 x 102)
= log(9.57) + log(102)
= 0.980911... + 2.00000... = 2.981
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23. In summary…
• on tests and the final exam,
• on homework assignments,
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24. Conversion Factors
• to convert a quantity from one unit to another,
we need to use a conversion factor
Dimensional Analysis
Quantity with Quantity with Conversion
desired unit = given unit X factor
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25. Example 1: Conversion factors
Convert 345.3 cm into metres.
Solution
100 cm = 1 m
1m
? m = 345.3 cm x = 3.453 m
100 cm
• N.B. the number of sig figs in the conversion
factor is infinite
!
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26. Example 2: Conversion factors
The density of the lightest metal, lithium (Li) is 5.34 x 102 kg/m3.
Convert this value to g/cm3.
Solution
1000 g = 1 kg 100 cm = 1 m
3 2 kg 1000 g 1 m %3
? g/cm = 5.34 x 10 3
• •$ ' =
m 1 kg # 100 cm
2kg 1000 g 1 m3
5.34 x 10 • • 6 = 0.534 g/cm3
m3 1 kg 10 cm3
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27. Density
mass
• density = ρ = volume
• density is a intensive property and is a very useful
conversion factor
!
• the SI unit is kg/m3, but we will most often use g/cm3
for solids and liquids and g/L for gases
1 g/cm3 = 1 g/mL = 1000 kg/m3
1 g/L = 0.001 g/mL
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28. Example : Using density
A piece of platinum has a density of 21.5 g/cm3 and a
volume of 4.49 cm3. What is its mass?
Solution
m
= ! m = •V
V
3 21.5 g Pt
? g Pt = 4.49 cm Pt • 3
= 96.5 g Pt
cm Pt
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29. Percent Composition
• number of parts of a component in 100
parts of the whole
– ex. 10% means 10 parts x per 100 parts of
the whole
• IMPORTANT: must be defined by a unit!
– ex. a rock contains 3.5% gold by mass
means 3.5 g of gold per 100 g of rock
– ex. a bottle of wine contains 10.7% alcohol
by volume means 10.7 mL of alcohol per
100 mL of wine
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30. Percent Composition
• when expressed as a conversion factor,
the numerator and denominator must
have the SAME UNITS
– ex. a rock contains 3.5% gold by mass
3.5 g gold 3.5 kg gold 3.5 oz gold
= =
100 g rock 100 kg rock 100 oz rock
– ex. a bottle of wine contains 10.7% alcohol
by volume
!
10.7 mL EtOH 10.7 L EtOH 10.7 tbsp EtOH
= =
100 mL wine 100 L wine 100 tbsp wine
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31. Example : Using percent composition
A solution of sucrose in water is 28.0% sucrose by mass
and has a density of 1.118 g/mL. What mass of sucrose
(in grams) is in 3.50 L of this solution?
Solution
1000 mL 1.118 g solution 28.0 g sucrose
? g sucrose = 3.50 L solution • • •
1L mL solution 100 g solution
= 1.10x10 3 g sucrose
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32. Chapter 1: Key Concepts
1. the forms and properties of matter
2. SI units and prefixes
3. accuracy vs. precision
4. significant figures
5. scientific notation
6. conversion factors
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33. Chapter 1: Suggested Problems
13, 14, 19, 20, 23,
27, 31, 45, 47, 51,
63, 65, 80, 81, 89
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