Chapter 2: Matter and How It Can Change

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Chapter 2 Matter and How It Can Change
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Properties of Matter

• Everything is made of matter
• Mass is the amount of matter (grams or kg)
• Volume is the space that the matter takes up (cm)
• Two main types of properties
• Physical properties A characteristic of a
  substance that can be measured or observed
  without changing the substances composition
• Intensive-dont change for a particular sample
  such as density, melting point, boiling point,
  color, solubility conductivity, ductility, and
  specific heat.
• Extensive- depend on size of matter such as
  length, mass, height, volume, and area.
• Chemical properties A characteristic of a
  substance that describes how it interacts with
  other substances to become something new.

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Changes in Matter

• Physical Change
• An alteration of matter that does not change the
  chemical composition of the material
• For example freezing or melting, boiling or
  condensing, cutting, grinding, bending, blending
• Chemical Changes
• Results in a change in the chemical composition
  of the substance(s) which is called a reaction.
• For example rusting, composting, tarnishing

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Practice Identifying Types of Changes in Matter
Chemical
Physical
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Chemical
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Chemical Reactions

• In a chemical reaction, one or more substances
  change into new substances by rearranging the
  atoms
• Copper nitric acid ? copper(II) nitrate
  nitrogen dioxide water
• Reactants ? Products
• The ability of a substance to undergo a chemical
  reaction and form new substances is called a
  chemical property.
• How to tell a chemical reaction has occurred.
• Heat is absorbed or given off.
• Change in color or odor.
• Production of a gas or solid.
• Law of Conservation of Mass
• During any chemical reaction, mass is neither
  created nor destroyed. The total mass of the
  system (products plus reactants) and the mass of
  each element is unchanged.
• Chemical Reaction Movies

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States of Matter

• Solid
• Definite shape and volume
• Very slight thermal expansion and almost
  incompressible
• Divided into subclasses of amorphous (or glassy)
  solids and crystalline solids
• Arrangements of atoms or molecules in crystalline
  solids are repeated regularly over a very long
  range of millions of atoms
• Arrangements in amorphous solids are somewhat
  random or short range of say some tens or
  hundreds of atoms.
• Liquid
• Indefinite shape (flows) and definite volume
• Moderate thermal expansion and almost
  incompressible
• Gas (Vapor)
• Indefinite shape and indefinite volume
• Great thermal expansion and readily compressible
• A vapor is the gaseous form of a substance that
  is normally solid or liquid at room temperature
• Plasma
• A very hot state of matter where atoms have been
  ripped apart into their smaller parts, protons
  and electrons.

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Animation
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Types of Matter

• Substances contains only one type of matter and
  has a uniform and definite composition
• Element
• Composed of just one type of atom. They cannot
  be separated into simpler substances using
  chemical means.
• They are represented by a chemical symbol (see
  Periodic Table).
• For example Gold (Au), Iron (Fe), Oxygen (O or
  O2)
• Compound
• Substances composed of two or more different
  kinds of atoms. The atoms are chemically
  combined to form a molecule (or formula unit).
• They are represented by a chemical formula which
  shows the elements and relative number of atoms
  in the compound.
• For example Water, H2O and Salt, NaCl.

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Types of Matter

• Mixtures a physical blend of two or more
  substances.
• Homogenous
• Transparent, uniform in composition, also called
  solutions.
• Can be separated by distillation, ion exchange,
  reverse osmosis
• For example Koolaid, salt water, and air
• Heterogeneous
• Opaque, not uniform in composition and appearance
• Can be separated by sieving , tweezing and
  skimming
• For example Milk, sand, bronze and blood