Chapter 2 Properties of Matter

Remember… Matter is anything that has mass and takes up space Can you name something that is not matter? What is the absence of matter called? –Vacuum

Extensive vs. Intensive Properties used to describe matter can be classified as extensive or intensive Extensive property – dependant on the amount of matter in a sample Intensive property – independent of the amount of matter in a sample

Examples Extensive: –Mass, volume, length Intensive: –Density, hardness, color

Substances Substance - Matter that has a uniform and definite composition Every sample of a given substance has identical properties because every sample has the same composition Examples of substances include copper, gold, mercury, water, and carbon dioxide.

Physical Properties Can be observed or measured without changing the substance’s composition Can you think of any physical properties? –Hardness, color, conductivity, malleability, melting point, boiling point, physical state

–Definite shape –Definite volume –Not easily compressed Plasma and Bose - Einstein condensates are 2 states of matter that are not as common

Physical Change – some properties of the material change, but the composition of the material stays the same May be reversible or irreversible Physical Changes

Boil, freeze, melt, condense Break, split, grind, cut, crush If the composition of the material changes, it is NOT a physical change.

Mixtures A mixture is a blend of 2 or more physical components Mixtures can be classified as heterogeneous or homogeneous

Mixtures Heterogeneous – composition is NOT uniform Homogeneous – uniform composition Homogeneous mixtures are sometimes called solutions A phase can be used to describe any part of a sample with uniform composition (example: 2 phases - oil and water)

Classifying Mixtures Food coloring Ice cubes in liquid water Mouthwash Mashed, unpeeled potatoes Olive oil Salt water Gasoline Chocolate chip ice cream

Separating Mixtures Physical properties can be used to separate mixtures Example: Assume you are asked to separate a mixture of olive oil and vinegar. You could decant (pour off) olive oil from vinegar. What physical property allows you to do this? You could cool the mixture until the oil solidifies, but the vinegar is still a liquid. What physical property allows you to do this?

Distillation A liquid is boiled to produce a vapor that is then condensed into a liquid. put in pic of dist set up

Elements and Compounds An element is the simplest form of matter A compound two or more elements that are chemically combined in a fixed proportion Compounds can only be broken down by chemical means (not physical)

Elements and Compounds Compounds usually have properties that are quite different from those of their component elements. Can you think of any examples? NaCl, H 2 O, C 6 H 12 O 6

Matter Map

Chemical Changes The composition of the matter always changes Examples include: burning, rotting, rusting, decomposing, fermenting, exploding, and corroding

Chemical Reactions There are four clues that provide evidence of a chemical change: –Transfer of energy –Change in color –Production of a gas –Formation of a precipitate

Chemical Reactions Be careful, the clues are only indicators that a chemical change may have occurred. What is the only way to tell for sure that a chemical reaction has taken place?

Law of Conservation of Mass During any chemical reaction, the mass of the products is equal to the mass of the reactants In any physical change or chemical reaction, matter can neither be created or destroyed.

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