Chapter 1 Introduction: Matter and Measurement

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Chapter 1IntroductionMatter and Measurement
Chemistry, The Central Science, 10th
edition Theodore L. Brown H. Eugene LeMay, Jr.
and Bruce E. Bursten

• John D. Bookstaver
• St. Charles Community College
• St. Peters, MO
• ? 2006, Prentice Hall

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• Why Study Chemistry
• Turn to page 3.
• Every aspect of our lives are based on chemistry.
• Microscopically (vs. macroscopically), everything
  is composed of atoms.
• Is a tool to help understand and the world around
  you.

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• General Definitions
• Chemistry study of the properties of materials
  and the changes that the material undergoes.
• Matter The physical material of the universe
  anything that has mass and takes up space.
• Elements A substance that cannot be separated
  into simpler substances by chemical means.
• Atoms Building blocks of matter, the smallest
  representative particle of an element.
• Molecules Atoms that are held together in
  specific shapes.

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Chemistry

• The study of matter and the changes it undergoes.

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Chemistry

• Solid both a definite shape and definite
  volume
• Liquid distinct volume independent of its
  container, so specific shape
• Gas no fixed volume or shape

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Chemistry
Solid molecules held together tightly only
wiggling slightly Liquid molecules are
packed more closely together than gas, less
tightly than solid allows for molecules to slide
over each other Gas Molecules are far apart,
colliding only briefly with each other and with
the wall of the container

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States of Matter
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Matter

• Anything that has mass and takes up space.

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Matter

• Atoms are the building blocks of matter.

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Matter

• Atoms are the building blocks of matter.
• Each element is made of the same kind of atom.

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Matter

• Atoms are the building blocks of matter.
• Each element is made of the same kind of atom.
• A compound is made of two or more different
  kinds of elements.

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Classification of Matter
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Classification of Matter
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Classification of Matter
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Classification of Matter
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Classification of Matter
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Classification of Matter
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Classification of Matter
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Classification of Matter
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Classification of Matter
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Classification of Matter
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Mixtures and Compounds
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Scientific Method

• A systematic approach to solving problems.

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Properties and Changes of Matter
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Properties of Matter

• Physical Properties
• Can be observed without changing a substance into
  another substance.
• Boiling point, density, mass, volume, etc.
• Chemical Properties
• Can only be observed when a substance is changed
  into another substance.
• Flammability, corrosiveness, reactivity with
  acid, etc.

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Properties of Matter

• Intensive Properties
• Independent of the amount of the substance that
  is present.
• Density, boiling point, color, etc.
• Extensive Properties
• Dependent upon the amount of the substance
  present.
• Mass, volume, energy, etc.

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Changes of Matter

• Physical Changes
• Changes in matter that do not change the
  composition of a substance.
• Changes of state, temperature, volume, etc.
• Chemical Changes
• Changes that result in new substances.
• Combustion, oxidation, decomposition, etc.

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Chemical Reactions

• In the course of a chemical reaction, the
  reacting substances are converted to new
  substances.

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Chemical Reactions
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Compounds

• Compounds can be broken down into more elemental
  particles.

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Electrolysis of Water
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Separation of Mixtures
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Distillation

• Separates homogeneous mixture on the basis of
  differences in boiling point.

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Distillation
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Filtration

• Separates solid substances from liquids and
  solutions.

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Chromatography

• Separates substances on the basis of differences
  in solubility in a solvent.

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Units of Measurement
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SI Units

• Système International dUnités
• Uses a different base unit for each quantity

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Metric System

• Prefixes convert the base units into units that
  are appropriate for the item being measured.

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Volume

• The most commonly used metric units for volume
  are the liter (L) and the milliliter (mL).
• A liter is a cube 1 dm long on each side.
• A milliliter is a cube 1 cm long on each side.

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Uncertainty in Measurements

• Different measuring devices have different uses
  and different degrees of accuracy.

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Temperature

• A measure of the average kinetic energy of the
  particles in a sample.

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Temperature

• In scientific measurements, the Celsius and
  Kelvin scales are most often used.
• The Celsius scale is based on the properties of
  water.
• 0?C is the freezing point of water.
• 100?C is the boiling point of water.

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Temperature

• The Kelvin is the SI unit of temperature.
• It is based on the properties of gases.
• There are no negative Kelvin temperatures.
• K ?C 273.15

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Temperature

• The Fahrenheit scale is not used in scientific
  measurements.
• ?F 9/5(?C) 32
• ?C 5/9(?F - 32)

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Density

• Physical property of a substance

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Uncertainty in Measurement
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Significant Figures

• The term significant figures refers to digits
  that were measured.
• When rounding calculated numbers, we pay
  attention to significant figures so we do not
  overstate the accuracy of our answers.

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Significant Figures

• All nonzero digits are significant.
• Zeroes between two significant figures are
  themselves significant.
• Zeroes at the beginning of a number are never
  significant.
• Zeroes at the end of a number are significant if
  a decimal point is written in the number.

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Significant Figures

• EXAMPLES
• Sig Fig Rule(s) Applied
• 0.021
• 1064
• 0.3007
• 14.232
• 4300.00
• 0.05082

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Significant Figures

• When addition or subtraction is performed,
  answers are rounded to the least significant
  decimal place.
• When multiplication or division is performed,
  answers are rounded to the number of digits that
  corresponds to the least number of significant
  figures in any of the numbers used in the
  calculation.

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Significant Digit Calculations
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Significant Figures

• Multiplication
• (a x 10x) x (b x 10y) ab x 10xy
• Division
• (a x 10x) / (b x 10y) ab x 10x- y
• Addition/Subtraction
• powers must be the same coefficients are then
  added or subtracted and the exponent is maintained

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Accuracy versus Precision

• Accuracy refers to the proximity of a
  measurement to the true value of a quantity.
• Precision refers to the proximity of several
  measurements to each other.

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Dimensional Analysis

• Metric System
• Unit label
• What do you have? I have 3.
• How much coffee do you want? I want four.
• Metric based off
• Unit US Metric
• Weight/Mass
• Length
• Volume

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Dimensional Analysis

• Conversion Factor - ratio that converts a
  measure expressed in one unit to a measure
  expressed in another unit. Always equal to 1

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Dimensional Analysis

• Road Mapping - way to dissect and solve problems
• SCC ? Chicago?
• Given Known Question

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Dimensional Analysis

• Example
• A vitamin C tablet is found to contain 0.500 g of
  vitamin C. How many milligrams of vitamin C does
  this table contain?
• Given Known Question

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Dimensional Analysis

• Example
• A piece of copper metal has a mass of 17.6 lb.
  What is the copper mass in kilograms?
• Given Known Question

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Dimensional Analysis

• Example
• The estimated amount of recoverable oil from the
  field at Prudhoe Bay in Alaska is 4.0 x 1011 gal.
  What is the amount in fluid ounces (fl. Oz)?
• Given Known Question