What is Chemistry

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What is Chemistry?

• Chapter 1.1

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Chapter Objectives

• Distinguish between physical and chemical changes
• Define and classify matter by composition
• Identify observable characteristics of a chemical
  reaction
• Explain and apply the fundamental law of
  conservation of mass

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Chemistry

• Chemistry is the central science, between Biology
  (life science) and Physics (physical science)
• Chemistry is the science of Matter. It
  investigates the composition, structure and
  behavior of matter.
• What is Matter?
• Anything that takes up space and has mass
• Mass measure of the amount of matter in an
  object

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Matter

• What does structure of matter refer to?
• Composition what makes it up
• Organization how it is made up
• The Properties of matter describe its
  characteristics and behavior
• Physical Properties
• Chemical Properties

H-H
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View of Matter

• Macroscopic Matter large enough to be viewed.
• You can see, touch, smell, taste
• The appearance of matter is a result of its
  structure. It is a property that is not
  immediately visible.

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Matter - Submicroscopic View

• Submicroscopic method is describing the world of
  atoms.
• Atom is the smallest particle of a given piece of
  matter
• Models are used to represent what we think atoms
  look like.

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Models in Chemistry

• Scientific Model A device used to help you
  understand and explain observations
• Atomic model developed in the 1800s

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Classifying Matter

• Qualitative - What is it made of? It is
  descriptive and doesnt involve measurement.
• Sugar Carbon, Hydrogen, Oxygen
• Quantitative How much is it made of? This
  measures some aspect of matter.
• 100 g of sugar (sucrose) 42.1g carbon, 51.4 g
  oxygen, 6.5 g hydrogen

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Elements

• The Periodic Table
• Organization of all the known elements
• Generally, metals are at the left and center of
  the table, non-metals at the right of the table
  When writing a formula of a metal and non-metal,
  list the metal first, then the non-metal.
  Example NaCl (sodium chloride)

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Definitions to Know

• Pure Substances Elements and Compounds
• Mixture
• Separation of mixtures
• Heterogeneous Mixture
• Homogeneous Mixture
• Alloy
• Solute
• Solvent
• Solution

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What is Matter?Activity
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Classifying Matter

• Is it pure or a mixture?
• Pure Every bit of the matter is the same
  substance.
• Substance matter with the same fixed
  composition and properties
• Can be an element simplest form of matter and
  cant be broken down further by chemical means
• Or can be a compound fixed ratio of elements in
  a substance

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Classifying Matter

• Mixture A combination of two or more substances
  in which the basic identity of each substance has
  not changed.
• Mixtures can be of any proportion
• Mixture can be separated by physical processes
• Solubility Boiling
• Melting Point Dissolving
• Evaporation Crystallization

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Types of Mixtures

• Heterogeneous Mixture
• One with different, distinct regions (Phases)
• Examples Orange juice liquid (juice) and solid
  (pulp),
• Granite Rock (see distinct types of rock)
• Lava lamp (liquids with different viscosities
  and heat capacities)
• Fresh milk (See cream separate from the liquid)

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Types of Mixtures

• Homogeneous Mixtures
• Mixture has a constant composition throughout
• Examples Sugar in water (cannot pick out sugar
  crystals in the water)
• Also called a SOLUTION

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Matter
Can it be separated by Physical methods?
No
Yes
Mixture
Pure Substance
Is it uniform?
Can it be separated by Chemical methods?
Yes
No
Yes
No
Homogen.
Heterogen.
Compound
Element
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Types of Solutions

• Alloy Solid solutions that contain different
  metals and sometimes non-metal substances
• Steel Iron, carbon, chromium, manganese,
  nickel, molybdenum
• Gold Jewelry Gold silver and copper

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Types of Solutions

• Liquid Solutions
• Solute what is being dissolved
• Example Sugar in coffee, salt in the ocean,
  grease in turpentine,
• Solvent The substance that dissolves the solute
• When the solvent is water, the solution is AQUEOUS

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Substances Pure Matter

• Pure Substances
• The material is made up of only the one
  substance.
• Two types of pure substances
• Element Copper, Iron, Carbon, etc.
• There are only 90 naturally occurring elements
  (the other 20 are synthetic)
• All other substances are made up of these
  elements

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Substances Pure Matter

• Two Types of Pure Substances (Continued)
• Compound A chemical combination of two or more
  different elements joined together in a fixed
  proportion.
• Examples Water (H2O)
• Sugar (C12H22O11)
• Chemical Formula a combination of the chemical
  symbols that show what elements make up the
  compound and the number of atoms of each element.