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
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.