Ch. 2

MATTER AND CHANGE

Ch. 2.1DESCRIBING MATTER

• Observation: using your senses to describe.– White, waxy substance

• Inference: making a conclusion– made of wax.

DESCRIBING MATTER

• Qualitative: describing matter using the senses.– White, smooth, circular, smells like

flowers, warm• Quantitative: numerically descriptive

– 8.5 cm high, weighs 85 grams.

DESCRIBING MATTER

• Extensive Property: depends on the amount of the sample. (can vary from sample to sample even if same substance)– Weight, volume, height, shape

• Intensive Property: depends on type (composition) of substance. (doesn’t change as long as samples are made of same substance)– Color, melting point, reaction with

other things

Give examples of extensive and intensive properties of these 2 samples of Silicon

Identifying Substances

• Physical Property: quality/condition of substance that can be observed or measured w/o changing substance.– Color, weight, size, volume

• ,

Identifying substances

• Physical Change: changing the state but not the composition.

• Melting, boiling, vaporizing, freezing, crushing

• dissolving

Identifying Substances

• Chemical Property: how a substance react with another substance.– Iron reacts with oxygen.

• Chemical Change: the reaction that takes place when two substances react (Chemical Reaction).Composition changes. (observe bubbling, color change, precipitate

• Iron reacts with oxygen to make rust.

States of Matter

• Solid: definite shape and volume

• Liquid: indefinite shape, flows, definite volume.

• Gas (Vapor): indefinite shape and volume, flows.

Review questions• Explain why all samples of a given

substance have the same intensive properties

• Explain why samples of gold and copper can have the same extensive properties, but not the same intensive properties

• How are the three states of matter involved when a candle burns?