Chapter 3 Matter

The Questions Why do is the sun hot? Why does wood burn whereas rocks do not? What is flame? How does soap work? Why does soda frizz when you open the bottle?

Matter Define as the “stuff” of which the universe is composed, has two characteristics: It has a mass and it occupies space. Three states of matter: Solid Liquid Gas

The Three States of Matter Definition Examples Solid Rigid, has a fixed shape and volume Ice cube, diamond, iron bar Liquid Has a define volume but takes the shapes of its container Gasoline, water, alcohol, blood Gas Has no fixed volume or shape; take the shape and volume of its container Air, helium, oxygen

Physical and Chemical Properties and Changes Physical properties Characteristics that do not involve a change in a sample’s chemical makeup. E.g Temperature, color, amount, melting point, solubility…. Chemical properties Characteristic that do involve a change in chemical makeup E.g rusting of iron, combustion etc…

Examples Classify each of the following as a physical or a chemical property The boiling point of a certain alcohol is 78oC Diamond is very hard Sugar ferments to form alcohol A metal wire conducts an electric current

Physical Changes Involves a change in one or more physical properties, but no change in the fundamental components that make up the substance Solid  liquid  gas

Chemical Change Involves a change in the fundamental components of the substances; a given changes into a new different substance or substances Also called as chemical reactions E.g Combustion of propane Propane + oxygen gas  Carbon dioxide +water vapor

Example Classify each of the following as a physical or a chemical change Iron metal is melted You make scrambled eggs Wood burns in air A rock broken into smaller pieces

3.3 Elements and Compound Classify as a pure substance Have a constant composition Element is a substance that cannot be broken down into other substance by chemical method Compound is a substance that composed of 2 or more elements or any substance that can be broken down into elements element + element  compound compound  element + elements + ….

3.4 Mixtures and Pure Substances Mixtures: formed when 2 or more substances are blended together in some random proportion Individual substances do not undergo a chemical change Homogeneous mixture (solution) has uniform properties throughout. E.g – water-base solutions Air: mixture of N2(g), O2(g) Heterogeneous mixture has regions with different composition E.g – Sand with sugar, water with gasoline, dust with air

Examples Identify each of the following as a pure substance, a homogeneous mixture, or a heterogeneous mixture Gasoline Brass Pure apple juice Chocolate chip cookies

3.5 Separation Mixtures Physical methods Gravity Suction Distillation Filtration Gravity Suction Common separation Homogeneous mixture Heterogeneous mixture

Distillation Separate solid from liquid E.g – Separation of salt water Volatile substance is readily separated through heating Composition of each individual substance does not changed E.g – Separation of salt water If two solutions are volatile then distillation cannot be achieved

Filtration Used to remove impurities from solution Impurities (larger solid particles) stay on the filter paper Water goes through the paper E.g – sand and seawater

Summary