Honors Chemistry

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Honors Chemistry

• Chapter 1
• The Study of Change

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1.1 1.2 Chemistry

• The study of matter and the changes it undergoes
• Structure and properties of matter
• Macroscopic vs Microscopic
• Structure (microscopic) determines properties
  (macroscopic)

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1.3 Scientific Method

• Systematic approach to research
• Based on data gathered by observation
• Qualitative general observations
• Quantitative numeric data
• Evolution of ideas
• Hypothesis tentative explanation testable
• Theory unifying principle that explains
  observations
• Scientific Law mathematical relationship

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1.4 Classification of Matter

• Matter anything with mass and volume
• Substance matter with definite composition and
  distinct properties
• Element cannot be separated into simpler
  substances (ie, only one type of atom present)
• Examples aluminum, gold, sulfur, oxygen, neon
• Compound two or more elements chemically
  combined in fixed proportions
• Examples water, sulfuric acid, rust, baking soda

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1.4 Classification of Matter

• Mixture combination of two or more substances
  which retain their identities
• Homogeneous mixture composition of mixture is
  uniform throughout
• Examples saltwater, air, metal alloys
• Heterogeneous mixture composition is not
  uniform phase boundaries
• Examples salt and pepper, oil and water, salad
  dressing

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1.4 Classification of Matter
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1.5 States of Matter
sublimation
vaporizing
melting
solid
liquid
gas
condensing
freezing
deposition
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1.6 Properties of Matter

• Physical property
• can be observed without changing the identity of
  the substance
• Physical change
• remains the same substance
• Extensive property
• Depends only on the amount of matter present
• Intensive property
• Depends on the type of matter present

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1.6 Properties of Matter

• Chemical property
• Property involving reactions with other
  substances
• Chemical change
• New substance is produced
• Classify the following properties
• Color, mass, flammability, solubility, density
• Classify the following changes
• Rusting, cutting, melting, burning, dissolving

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1.7 SI Units

• Système Internationale dUnites
• International System of Units

Base quantity Name Symbol
length meter m
mass kilogram       kg
time second s
electric current ampere A
temperature       kelvin K
amount of substance mole mol
luminous intensity candela cd



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1.7 SI Conversions
Factor Name  Symbol
1024 yotta Y
1021 zetta Z
1018 exa E
1015 peta P
1012 tera T
109 giga G
106 mega M
103 kilo k
102 hecto h
101 deka da
Factor Name  Symbol
10-1 deci d
10-2 centi c
10-3 milli m
10-6 micro µ
10-9 nano n
10-12 pico p
10-15 femto f
10-18 atto a
10-21 zepto z
10-24 yocto y
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1.7 SI Conversions
m
unit
m
c
d
M
G
T
p
n
da
h
k
3 decimal places
3 decimal places
1 decimal place
Multiply number of decimal places by the
dimensionality of the unit
Some Practice
0.173
25 000
17.3 cm ______ m
0.025 kg ______ mg
986
0.000 058 7
0.986 dm3 ______ cm3
587 nm __________ cm
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1.7 Derived Units

• Mathematical combinations of base units
• Area Alw m?m m2
• Volume V lwh m ? m ? m m3
• dm3 Liter cm3 mL
• Density r m/V kg/m3, g/cm3, g/mL
• Mass vs. Weight
• Mass amount of matter kg
• Weight force of gravity N

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1.7 Temperature Scales
Fahrenheit
Celsius
Kelvin
Boiling Point
212oF
100oC
373.15 K
Human bodytemp 100oF
Freezing Point
32oF
0oC
273.15 K
Coldest temp in lab 0oF
Absolute Zero
-460oF
-273.15oC
0 K
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1.7 Temperature Conversions

• Celsius-Kelvin offset by 273.15o
• K oC 273.15
• oC K 273.15
• Celsius-Fahrenheit
• Offset by 32oF
• Different sized degrees 9Fo 5Co
• oC 5/9 (oF - 32)
• oF 9/5 oC 32
• Convert 98.6oF to oC and to K

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1.8 Scientific Notation

• m x 10n
• 1 m lt 10
• Exponentiation ? multiply exponents
• Multiplication ? Add exponents
• Division ? Subtract exponents
• Addition/Subtraction ? must have same exponent

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1.8 Significant Digits
Digits which were actually measured, as opposed
to placeholder zeroes
Consider...how long is the blue rectangle?
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2
3
4
5
cm
Estimate the next digit
Read 2 cm
2.4 cm 0.1 cm
Lets use a better ruler
uncertainty in measurement dx
measurement x
Now how long is the rectangle?
2.43 cm 0.01 cm
Implied 1 on last digit of all measurements
unless told otherwise
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1.8 Significant Digits

• Rules of thumb to deal with calculations
  involving significant digits
• Addition/Subtraction
• Round to the decimal place of the least precise
  value
• Multiplication/Division
• Round to the number of digits of the least
  precise value
• Answers must be rounded properly!

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1.8 Relative Error

• Compare uncertainty to measurement
• dx RE ------ x
• Often expressed as a percent
• With laboratory data, dx is found by comparing
  experimental result to theoretical expectations
• xth xexp RE ---------------
  xth

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1.8 Accuracy and Precision

• Accuracy
• how close a measurement is to the correct value
• How close were you to the bulls eye?
• Precision
• how closely a set of values agree with each other
• Were your shots clustered or scattered?
• Lets measure the bp of water 3 times
• Accurate but not precise 96oC, 101oC, 104oC
• Precise but not accurate 57.2oC, 56.8oC, 57.1oC

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1.9 Dimensional Analysis

• Technique for solving problems by treating units
  of measure as algebraic quantities
• Set up conversion factors
• 18 in __________ ft
• We know 1 ft 12 in
• 18 in 1 ft------- x -------- 1
  12 in

1.5 ft
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1.9 Dimensional Analysis

• Convert the speed of light (3.00 x 108 m/s) to
  miles / hour.
• 3.00 x 108 m 1 km 1 mile 3600
  s------------------ x ---------- x ---------- x
  -------- 1 s 1000 m 1.6 km
  1 hr
• 6.8 x 108 mi/hr
• 2 sig dig because of km mile conversion
• That wasnt so bad, was it?