Chapter 2: Matter

Sections 2.2 & 2.3

2.2 Properties of Matter

• Objectives• To learn to distinguish between

physical and chemical properties• To learn to distinguish between

physical and chemical changes

Physical Property

• Characteristic of a substance that can change without changing the substance’s composition.

Physical Change

• A change that does not affect the composition of a substance

Examples of Physical Changes

• Melting/ Freezing• Vaporizing/ Condensing• Cutting• Grinding• Squishing

Chemical Property

• Characteristic that describes the ability of a substance to change into a different substance.

Chemical Change

• Change in which a substance becomes a different substance.

Examples• Flammability (burning)• Exploding• Fermenting• Digesting• CorrodingTarnishingRusting

Evidence of a chemical change

Evidence of a chemical change

• Formation of bubbles• Formation of a precipitate (a solid)• A color or odor change• Heat, Cold and/ or light evolves

2.3 Classifying Matter

• Objectives• To learn to distinguish between

mixtures and pure substances.• To learn two methods of separating

mixtures.

Mixtures and Pure Substances• Mixtures

• Defined as something w/ a variable composition.• Examples:

− Soda – water, sugar, carbon dioxide− Sea water – water, minerals, salt, etc.− 14 carat gold – 36% gold, 25% silver, 37%

copper− Dirt− Air – nitrogen, oxygen, argon, helium, neon,

carbon dioxide, water vapor, etc.

2 Types of Mixtures

• Homogeneous Mixture: mixture that is the same throughout. Can also be called… solutions!

• Heterogeneous Mixture: mixture containing regions of varying composition.

Heterogeneous or Homogeneous Mixture?

Separation of Mixtures

• Mixtures can be separated utilizing each substances physical properties.

• There are several ways to separate mixtures…• Use a magnet• FILTRATION• DISTILLATION• Picking it out

Distillation

• A separation process that depends on the different boiling points of the substances.

Filtration

• Separation of a solid from a liquid by using filter paper.

Mixtures and Pure Substances

• Pure Substances• Always has the same composition, no

matter what!• Can be

• Elements− See Periodic Table

• Compounds− There are millions!!!!!!

− H2O, NaOH, Al2(SO4)3, NaCl, C6H12O6