Matter and Measure

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Unit 1

• Matter and Measure

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Measure
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Scientific Measurement

• Two main systems
• English
• Based on arbitrary measurements that have lasted
  through history
• Conversions are harder to remember
• Metric
• Based on powers of ten
• Prefixes determine magnitude of power of ten

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International System (SI)

• Scientific Community has accepted certain units
  as base units

Dimension Unit Symbol
Length Meter m
Mass Gram g
Time Second s
Temperature Kelvin K
Amount Mole mol
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Metric System Prefixes
Prefix Power Symbol
Giga 109 G
Mega 106 M
kilo 103 k
deci 10-1 d
centi 10-2 c
milli 10-3 m
micro 10-6 µ
nano 10-9 n
pico 10-12 p
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Measuring

• Digital Displays are recorded as is
• Digital Mass Balance, pH meter
• Visually Read Scales can always be estimated to
  smaller increment than marked
• Rulers, Thermometers, Graduated Cylinders
• Meter stick Example

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Example

• Length??
• 0.3m 0.31m 0.314m

0m
0.4m
0.2m
0.1m
0.3m
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Significant Figures (sigfigs)

• Not all digits(s) in a measurement are
  significant(important)
• Suppose the mass of an object is estimated to be
  2.5 grams
• The volume of that object is measured accurately
  to 0.6250000cm3
• How many decimal places should the density have?
  4.0g/cm3 or 4.000000g/cm3

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Significant Figures (cont)

• Rules on pages 66-71 of textbook
• Shorthand
• If the decimal point is present, start counting
  digits from the Pacific (left) side, starting
  with the first non-zero digit.

? 1 2 3 0.00310 (3 sig. figs.)
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Significant Figures (cont)

• Shorthand
• If the decimal point is absent, start counting
  digits from the Atlantic (right) side, starting
  with the first non-zero digit.

3 2 1 ? 31,400 (3 sig. figs.)
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SigFigs for Math

• Addition and Subtraction
• Answer has to have the same number of decimal
  places as least decimal places in what you are
  adding or subtracting
• Example
• 15.62-7.248 ???
• Calculator ? 8.372
• Science ? 8.37

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SigFigs for Math

• Multiplication and Division
• Answer has to have same number of Sigfigs as
  least number of Sigfigs in what you are
  multiplying or dividing
• Example
• 7.550.34 ???
• Calculator ? 2.567
• Science ? 2.6

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Scientific Notation

• Short hand way of writing very large and very
  small numbers
• Uses only sigfigs
• Examples
• 602,000,000,000,000,000,000,000
• 6.02 x 1023
• 0.000000000567
• 5.67 x 10-10

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Accuracy

• How close a measurement is to correct or accepted
  value
• Bull's-eye on a dartboard

Poor Accuracy
Good Accuracy
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Precision

• How close a measurement is to other measurements
• Darts close to each other

Poor Precision Poor Accuracy
Good Precision Good Accuracy
Good Precision Poor Accuracy
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Percent Error
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Temperature

• Measure related to the heat of an object
• Measured in Celsius or Kelvin(no degrees)
• Conversion

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Density

• Amount of matter in a given amount of space
• Amount of mass in a given volume

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Matter
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Chemistry

• What is Chemistry?
• Study of matter and the changes it undergoes
• Branches
• Organic
• Physical
• Analytical
• Biochemical
• Inorganic

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IUPAC

• International Union of Pure and Applied Chemistry
• Group that names elements and compounds
• Meets every few years

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Matter

• Anything that has mass and takes up space, volume
• Classified into two categories
• Substances (Pure)
• Mixtures

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Atom

• Simplest form of matter
• Made up of Subatomic Particles
• Different atoms have different properties

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Pure Substances

• Element
• simplest form of matter that has a unique set of
  properties.
• arranged into a table, called the periodic table
• Cant be broken down by chemical means
• denoted using chemical symbols, O, Cu, Fe
• Symbols always have the first letter capitalized
• If needed, any additional letters are not
  capitalized

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Pure Substances (Cont)

• Compounds
• substance of two or more elements chemically
  combined in a fixed proportion
• Ex. H2O, C6H12O6
• Can be broken down by chemical means

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Mixtures

• Physical blend of two or more substances
• Two Types
• Homogeneous
• Heterogeneous

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Mixtures (cont)

• Homogeneous
• Composition is uniform throughout
• Examples Air, Olive Oil, Stainless Steel
• Solution is a homogeneous mixture
• Aqueous Solution is something mixed in water
• Heterogeneous
• Composition is not uniform throughout
• Examples Salad Dressing, Chicken Noodle Soup

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Separating Mixtures

• Differences in physical properties can be used to
  separate mixtures
• Filtration Separates solids from liquids in
  heterogeneous mixtures
• Distillation Separates homogeneous liquid
  mixtures based on different boiling points

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Separating Mixtures

• Evaporation evaporate away liquid to leave
  solid
• Chromatography separation of substances based
  on polarity

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Phases(States) of Matter

• Solid
• Definite shape and volume
• Particles are packed tightly together in a
  regular geometric pattern
• (s) used after chemical formulas
• Cu(s)

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Phases of Matter

• Liquid
• Definite volume, takes shape of container
• Particles can slide past each other
• (l) used after chemical formulas
• H2O(l)

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Phases of Matter

• Gas
• Takes shape and volume of container
• Particles are spread very far apart
• (g) used after chemical formulas
• H2O(g)

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Aqueous Solutions

• Dissolved in water
• (aq) used after chemical symbols
• NaCl(aq)

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Phase Changes

• Solid ? Liquid Melting
• Liquid ? Solid Freezing
• Liquid ? Gas Vaporization
• Gas ? Liquid Condensation
• Solid ? Gas Sublimation
• Gas ? Solid Deposition
• Temperature does NOT change during a phase change

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Identifying Substances

• Physical Property
• quality or condition of a substance that can be
  observed or measured without changing the
  substances composition
• Ex Color, shape, size, mass
• Physical Change
• some properties change, but the composition
  remains the same
• Can be reversible or irreversible
• Ex melting, freezing, tearing

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Identifying Substances (cont)

• Chemical Change
• change that produces matter with a different
  composition than the original matter
• Ex. burning, rusting, decomposing, exploding,
  corroding
• Chemical property
• property that can only be observed by changing
  the composition of the substance.
• Ex Reactivity with acids, reactivity with oxygen

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Physical or Chemical ?

• Boiling Point Physical
• Green color Physical
• Shiny Physical
• Conductivity Physical
• Solubility Physical
• Reacts with acid Chemical
• Reacts with O2 Chemical

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Describing Matter

• Extensive Properties
• property that depends on the amount of matter in
  a sample.
• Ex mass, weight, volume
• Intensive Properties
• property that depends on the type of matter in a
  sample, not the amount of matter
• Ex Density, hardness, viscosity

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Energy

• Capacity to do work
• Ability to do something
• Types
• Chemical
• Electrical
• Mechanical
• Potential
• Kinetic

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Energy Exchanges

• Exothermic
• Process when energy is released or given off
• Ex Burning, freezing
• Endothermic
• Process when energy is absorbed or taken in
• Ex Melting

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Scientific Method

• Observation
• using five senses to make observations.
• Hypothesis
• proposed explanation for an observation.
• Experiment
• procedure used to test a hypothesis.

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Scientific Method (cont)

• Analyze Data
• check to see if results support hypothesis.
• Theory
• well tested explanation for a broad set of
  observations.
• Law
• concise statement that summarizes the results of
  many observations and experiments.

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Scientific Laws

• Law of Conservation of Mass
• Mass can not be created or destroyed, only
  changed into different forms
• Law of Conservation of Energy
• Energy can not be created or destroyed, only
  changed into different forms