Chapter 2 Matter

Section 1: What is Matter? Matter—anything that has mass and takes up space Is air matter? How could you figure it out? There are two main categories of matter: substances and mixtures.

Substance—matter that is either an element or a compound; has definite chemical and physical properties.

Elements—matter that cannot be broken down into simpler substances by chemical processes, such as burning. Examples of Elements— Atom—the smallest unit of an element that keeps the properties of that element.

Compounds—matter that is made of atoms of 2 or more different elements that are chemically combined. Examples of Compounds: Molecule—the smallest unit of a substance that keeps the properties of that substance. Molecules of compounds are made of atoms of different elements, such as H2O for water. A molecule may also be made up of atoms from only one type of element, such as O2, oxygen gas. (SEE DIAGRAMS ON PG. 40) Chemical Formula—a combination of chemical symbols and numbers to represent a substance. Examples:

Mixture—a combination of 2 or more sub-stances that are NOT chemically combined. This means that the substances that make up a mixture can be separated from each other by physical processes, such as filtering or boiling. Mixtures do not always contain the same amounts of substances that make them up. There are 2 types of mixtures: homogeneous mixtures and heterogeneous mixtures.

Homogeneous Mixture—mixture in which 2 or more substances are uniformly spread-out; they look the same throughout. A.K.A. “solution” Examples— Heterogeneous Mixture—mixture in which the different substances can be easily distinguished.

Two Categories of Heterogeneous Mixtures Colloids—mixture in which the particles are large enough to scatter light, but they will never settle-out. Examples: Suspensions—mixtures in which the particles are large enough that they will settle-out.

To Summarize… Matter Pure Substances Elements Examples Compounds Mixtures Homogeneous Solutions Heterogeneous Colloids Suspensions

Check your understanding: Write each of the following types of matter into the correct category: water, oxygen, air, carbon-dioxide, smoke, muddy water, saltwater, steel, Kool-aid, fog, Italian dressing, salt (sodium chloride), carbon Compound Element Solution Colloid Suspension

Now, a short quiz… _________ has mass and occupies space. _________ cannot be broken down into simpler substances by chemical processes. Substances include _________ and _________. The formula H2O represents a ___________ of water. A mixture is a combination of substances that are not ___________ _____________. Classify each of the following into one of the categories below: salt water, pulpy orange juice, iron, carbon dioxide, fog Element Compound Solution Colloid Suspension