Section 1: Matter and Elements Unit 2: Matter and Atoms Section 1: Matter and Elements

How many different kinds of substances can you identify? What are things made of? How many different kinds of substances can you identify?

What are things made of? The “stuff” that we are made of is called matter. Chemistry tells us how one kind of matter can be changed into a completely different kind of matter.

Corn oil is a pure substance substance: a kind of matter that can’t be separated into other substances by physical means such as heating, cooling, filtering, drying, sorting, or dissolving.

Oil and vinegar dressing is a mixture of substances Corn oil is a pure substance mixture: matter that contains more than one substance.

Is “pure orange juice” a pure substance? Water Flavoring chemicals Citric acid Sugars Fruit pulp … The answer is “no.” Orange juice is composed of many kinds of substances mixed in together. “Pure orange juice”

Look at your desk – What is it made of? wood, metal… Can you think of a few physical properties? is it heavy? is it bendable? does it feel cold? can you scratch it? … In the next slide, students will see that they have been listing physical properties: properties that they can see and measure.

Physical properties Examples: Mass Density Color Physical properties can be measured or seen through direct observations.

Physical changes include changes in shape, phase or temperature.

Chemical properties are observed when a substance changes into a different substance. Chemical change Iron Rust

Signs that a chemical change has occurred

Macroscopic and microscopic scales