1. Chapter 1-3: Classifying Matter

2. Matter Anything that has volume and mass All matter is composed of atoms –An atom is the smallest unit of an element that maintains the properties of that element –Atoms can be physically mixed or chemically joined together to make up all kinds of matter

3. Pure Substances Pure substance –A sample of matter, either a single element or a single compound, that has definite chemical and physical properties –Examples include copper, oxygen, and carbon dioxide

4. Pure Substances Elements –Pure substances that contain only one type of atom –Each element has its own chemical symbol on the periodic table

5. Pure Substances Molecules –Elements can exist as single atoms or as molecules –A molecule is the smallest unit of a substance that keeps all the physical and chemical properties of that substance –It can consist of one atom or two or more atoms bonded together –Example: Helium versus Hydrogen

6. Pure Substances Compounds –A substance made up of atoms of two or more different elements joined by chemical bonds –Compounds can be made from their elements and also broken down into their components

7. Pure Substances –Compounds are represented by formulas H 2 O- subscripts are placed to the lower right of the symbol of the element Subscripts represent the number of elements in a compound, if only one atom is present, no subscript is used –Compounds can also be represented by structural formulas, ball and stick models, and space-filling models

8. Mixtures Mixture: A combination of two or more substances that are NOT chemically combined –Example: air is a mixture of nitrogen, oxygen, argon, and carbon dioxide –Example: pure water is NOT a mixture because H is chemically bonded to O to form H 2 O

9. Mixtures The proportion of the materials in a mixture can change Because of this the properties of mixtures may vary Examples: sweetened iced tea, 14-karat gold

10. Mixtures Homogeneous mixtures –When pure substances are distributed evenly throughout the mixture –The different components of the mixture cannot be identified by looking at it –Examples: air, gasoline, syrup

11. Mixtures Heterogeneous mixtures –When pure substances are NOT evenly distributed throughout the mixture –You can see the different components in the mixture –Different parts of the mixture may have different properties –Example: ice tea, cereal

12. Mixture v. Compound A mixture is composed of two or more substances that are physically mixed Properties of mixtures reflect the substances it contains Mixtures can have varying proportions Mixtures can be separated based on the physical properties of the substances A compound is composed of two or more elements chemically joined Properties of compounds have different properties than the elements that make them up Compounds have definite proportions Compounds can only be separated into its components through chemical change

13. Chapter 1 Vocabulary Chemical Chemical reaction States of matter ReactantProductMatterVolumeMassWeightQuantityUnit Conversion factor Physical property Density Chemical property Atom Pure substance ElementMoleculeCompoundMixtureHomogenousHeterogenous