1. Properties and Classification of Matter
Section A1.2

2. Objectives
distinguish between physical and chemical properties of substances
classify matter as pure substances or mixtures and further into homogeneous or heterogeneous
describe evidence for chemical changes

3. Matter Matter is anything that has a mass and takes up space
Desk, humans, Pepsi
All matter has both physical and chemical properties

4. Classifying Substances
Use two types of classification:
1) Physical properties
Physical appearance and composition of a substance
Ex. Boiling point
2) Chemical properties
Reactivity of a substance
Ex. Reaction with water

5. Physical or Chemical?
For the next properties, classify as physical or chemical and then place into a chart within your notes. Headings on your chart should be property, type, and definition.
Color?
Physical
Solubility?
Ability to burn?
Chemical (combustion)
Reaction to litmus?
Chemical

6. Physical or Chemical? Flash point? State? Ductility? Magnetism?
Chemical (temp to ignite flame)
State?
physical
Ductility?
Physical
Magnetism?
Reaction to heat?
Chemical (melt or decompose?)
Crystal formation?
What did we miss on p 13, Figures A1.1 and A1.2? Fill in the rest of your chart with that information

7. Physical change
In a physical change, matter takes on different characteristics by manipulating the properties, but no new substance is produced
Physical changes are usually reversible

8. Chemical change
In a chemical change, new substances are produced that have physical and chemical properties that are different from the starting reactants
Chemical changes are often non-reversible

9. There are many ways to produce light
A) light bulb (physical change)
B) laser (physical change)
C) lighter (chemical change)
D) burning magnesium (chemical change)

10. Pure Substances and Mixtures
Matter
Pure Substances
Elements
Compounds
Mixtures
Solutions
Mechanical mixtures
Suspensions
Colloids
homogeneous
heterogeneous
Fig. A1.9 p. 14

11. Do Now
Define each term in the chart (except matter) and provide an example for each

13. Pure Substances and Mixtures
All particles making up substance are identical
Physical and chemical properties constant
Ex. element/compound
Mixtures
Combination of pure substances
Properties vary with composition
Elements
Pure substance that cannot be broken down
One type of atom (ex. Helium)
Compounds
Chemical combination of 2 or more elements in specific ratio
Ex. water

14. Continued… Solution Mechanical mixtures Suspension Colloids
Separate components not visible (homogeneous)
One dissolved into another
Ex. Juice
Mechanical mixtures
Different substances visible (heterogeneous)
Ex. Soil
Suspension
Components in different states
Ex. Mud (dirt in water)
Colloids
Can’t easily separate the suspended substance
Ex. milk

15. Identifying Pure Substances
Observe chemical and physical properties
Does the physical property change the identity or composition of a substance?
Ex. Melting water: does the water itself change when we change states (solid to liquid)? Is this a pure substance or mixture?
Ex. Melting a solid produces a gas and a liquid? Is this a pure substance or a mixture?

16. Chemical Reactions Chemical change/chemical reaction
Process that occurs when something reacts to form something new
New substance has own physical and chemical properties
Energy always absorbed or released
How do we know that a chemical reactions has occurred? What signs do we look for?

17. Homework
Answer questions 6-9 on page 17

18. ACTIVITY A3 – Evidence of chemical change
Problem: What observable changes happen when a chemical reaction occurs?
Materials, Procedure: see p 16
Observations: Prepare a data table that includes space for the following reactions. For each reactant, record its observable characteristics before the reaction. Also record changes that you observe when you combine the reactants. Give your table a title.