1. Chem 11

2. Indications of a chemical reaction Energy absorbed or released Color change Gas produced Precipitate- solid that separates from solution Not easily reversed ALWAYS THERE IS A NEW SUBSTANCE!

4. Pure substance: contains one type of particle. –Elements: –Compounds:

5. Mixture: contains two or more types of particles intermingling, no chemical bonding. –Homogeneous: –Heterogeneous:

6. Composed of two or more different atoms Can be broken down by chemical methods and each part will have different properties Examples: water (H 2 O), 2 atoms of hydrogen, 1 atom of oxygen) salt (NaCl), 1 atom of sodium, 1 atom of chlorine

7. An element is a substance made up of only one kind of atom The periodic table arranges elements according to their properties

8. One kind of matter- Molecule or atom More than one kind of matter- different molecules or atoms Made during a chemical change Made through a physical change Definite and uniform composition Variable in composition

9. Which is it? Element Compound Mixture

10. has parts with different properties (composition is not uniform) Different kinds of particles stay together. Mechanical mixing Ex: sand and salt, blood, milk, pizza, sand, salad

11. Looks the same throughout (uniform composition) Particles are intermingled May be solutions (something dissolved) Ex: air, salt water, silver, sugar, salt

12. Homogeneous mixture with molecules mixed uniformly Solutions occur between any state of matter. Examples:Solid in liquid- Kool-aid Liquid in liquid- antifreeze Gas in a liquid – carbonated beverages Gas in gas- air Solid in solid - brass Liquid in gas- water vapor

13. Like all mixtures, the components keep their own properties. Components can be separated by physical means

14. They cannot be separated physically!! …… but mixtures can! Examples of physical separation: magnetic boiling points-distillation filtration

15. SEPARATION OF A HETEROGENEOUS MIXTURE Separation based on physical method. Magnetic property of the iron.

16. MIXTURES MAY BE HOMOGENEOUS OR HETEROGENEOUS EACH COMPONENT KEEPS ITS IDENTITY CAN BE PHYSICALLY SEPARATED THE COMPONENTS CAN BE COMBINED IN MANY PROPORTIONS

17. Classification of Matter