Study Guide

1
Chapter 17

• Study Guide

2
Matter

• Matter is classified as substances and mixtures.
• Matter has mass and takes up space
• Mixture composition variable, can be separated
  by a physical means
• Element composition definite
• Compound two or more elements combined

3
Pure Substances

• Element
• matter composed of identical atoms
• All atoms are the same
• EX copper

4
Classifying Matter

• Colloid vs. Solution-pass a beam of light through
  the mixture
• If the beam is invisible- it is a solution
• If the beam is visible- it is a colloid
• The visible beam through the colloid is called
  the Tyndall effect
• Suspension- heterogeneous mixture containing a
  liquid in which visible particles settle out over
  time like dirty water and Italian salad dressing

5
Mixtures

• Variable combination of 2 or more pure substances.

• Homogeneous Mixture (AKA -Solution)
• even distribution of components
• very small particles
• particles never settle
• EX saline solution, fresh pickle juice

6
Mixtures

• Heterogeneous Mixture
• uneven distribution of components
• colloids and suspensions
• EX granite

7
Pure Substances

• Compound
• matter composed of 2 or more elements in a fixed
  ratio
• properties differ from those of individual
  elements
• NOT a mixture
• EX salt (NaCl)

8
Mixtures

• Colloid
• medium-sized particles
• Tyndall effect - particles scatter light (looks
  cloudy)
• particles never settle
• EX milk, fog

9
Tyndall Effect
Because of the Tyndall effect, A light beam
is Scattered by the Colloid suspension On the
right, but Passes invisibly Through the
solution On the left.
10
Physical Properties

• Physical Property- any characteristic of a
  material that you can observe or attempt to
  observe without changing the identity of the
  substance
• For example color, shape, size, melting point,
  and boiling point, how it flows.
• Metallic aluminum Silvery color, easily formed,
  reflects heat.
• Behavior of substances- magnetism, ductility-
  ability of metal to be drawn into wires
  malleability- ability of metal to be shaped-
  pounded into sheets ability to flow

11
Physical Change

• A change in the form of a substance without
  changing its identity.
• properties remain the same
• reversible
• can be used to separate mixtures
• EX dissolving, grinding, distillation, mixing
  sugar and salt

12
Physical Changes

• Distillation- separating a solution of two
  liquids through evaporating
• a liquid and
• re-condensing
• its vapor.
• Vapors from the liquid
• with the lowest boiling
• point form first and are
• condensed and
• collected

13
Chemical Property

• A characteristic that indicates whether a
  substance can undergo a specific chemical change.
• EX flammability, reactivity, resistance of a
  diamond to corrosion
• Chemical changes can be used to separate
  substances- done in labs- metals can be removed
  from ore this way

14
Chemical and Physical Weathering

• Weathering-
• Physical weathering when rocks split as water
  freezes or as erosion occurs
• Chemical weathering when acidic water reacts with
  limestone and results in a new substance that
  dissolves in water and washes away.

15
Law of Conservation of Mass

• Mass cannot be created or destroyed
• Burning a log seems to make mass disappear
• missing mass is actually present in the gases
  that are produced as the log burns
• When the log burns new substances are formed.
• EX Iron and oxygen combining to form rust, the
  masses will still be equal.