Chemistry Notes: Matter

Objectives I can… Classify matter Describe the types of properties Atoms, molecules, compounds, mixtures, etc. Describe the types of properties Physical, chemical, intensive, extensive Explain at the molecular level chemical and physical changes

Matter Terms you should know: Matter can be classified Matter, mass, volume, density Matter can be classified Elements Compounds Substances Mixtures

Matter All matter is made up of atoms Atoms –smallest particle of an element - can be broken down into and still maintain the properties of that element. Atoms are particles in elements.

Matter Elements – A substance that cannot be chemically separated into simpler substances. Each element has its own symbol (e.g. Iron  Fe)

Matter Compounds – Two or more different elements that are chemically combined Compounds are represented by chemical formulas (e.g. Magnesium Chloride  MgCl2) Sodium Dichromate

Matter Molecules – Two or more (of any) atoms that are chemically combined Molecules are also represented by chemical formulas (e.g. H2, S8, HCl, NaOH) A molecule can be a diatomic element, polyatomic element, or a compound

Matter What is the difference between a compound and a molecule? Which one are compounds/molecule?

Classifying Matter Matter Chart

Classifying Matter Pure Substances Elements Monoatomic - elements whose atoms do not naturally bond (e.g. He, Ne, Ar, etc.) Diatomic – elements whose atoms bond in two atom units Polyatomic – elements composed of multi-atom units (e.g. P4, S8, O3)

Classifying Matter Pure Substances Compounds Organic – carbon based compounds Inorganic – non-carbon based compounds

Classifying Matter Mixtures – A combination of two or more substances in which each substance retains its own chemical identity.

Classifying Matter Types of Mixtures Homogeneous – mixture that appears the same throughout under a microscope. Ex: Solutions Solvent – substance doing the dissolving Solute – substance being dissolved

Classifying Matter Types of Mixtures Heterogeneous – mixture that has a different appearance in different parts of the substance. Ex: granite, sand, chocolate chip cookies

Classifying Matter Types of Mixtures Heterogeneous (cont.) Colloids: a heterogeneous mixture that never settles Ex: gelatin Tyndall Effect: the scattering of light by a mixture Suspension: a heterogeneous mixture where the particles are visible and settle.

Classifying Matter The Tyndall Effect – in the example below the laser is seen in the colloid but not the solution (homogenous mix.).

Properties of Matter Properties of matter allow us to distinguish one substance from another.

Properties of Matter Types of properties Physical – can be measured without changing the chemical make up of a substance EX: color, odor, density, melting point, etc.

Properties of Matter Types of properties Chemical – properties that describe the way one substance will react with another EX: Flammability, reactivity, etc.

Properties of Matter Types of properties Intensive Properties – determine the identity of substances. Tells you WHAT substance you have Melting Point, Density, specific heat, etc.

Properties of Matter Types of properties Extensive Properties – determine quantity of sample. Mass, volume, length dimensions, etc.

Changes in Matter Physical Change – change in appearance but not in composition. You still have the same substance after the change. EX: Tearing paper

Changes in Matter Chemical Change – changes in composition. New substances are formed after the change. EX: Burning paper Reaction between Cl- and CH3I

Summary Know the basics classification of matter Atoms, molecules, compounds, mixtures, etc. Know the types of properties Physical, chemical, intensive, extensive Be able to describe chemical and physical changes