Chapter 2 Vocabulary Mass: The amount of matter a substance has; different from ‘weight’ which is dependent on gravity. Volume: The space occupied by an object. Matter: Any substance that takes up space (volume) and has mass.

Physical Versus Chemical Properties Physical Property: A quality or condition of a substance that can be measured without changing the substance’s composition (chemical structure). Color, state, melting point, freezing point are examples Physical Change: During a physical change, some properties of the substance change, but the composition of the material does NOT change. Phase changes are an example Physical changes can be reversible (phase changes) or irreversible (broken glass).

Mixtures: A physical blend of two or more substances Homogenous Mixture: When the composition of the mixture is EVEN throughout. Every sample of the mixture would contain the same ratio of substances. A SOLUTION is another name for a homogenous mixture. Brass is an example (even mixture of copper and nickel) Heterogeneous Mixture: When the composition of the mixture is NOT uniform throughout. Chicken noodle soup is an example

Elements and Compounds Element: The simplest form of matter that has a unique set of properties. (Think Periodic Table!) Compound: A substance that has two or more elements chemically combined in a fixed proportion. examples: H2O, CO2, NaCl, C6H12O6 Compounds CAN be broken down into elements by chemical means, but elements CANNOT. Chemical Change: A change that produces matter with a different chemical composition than the original matter.

Possible clues to chemical change include (1) a transfer of energy (2) a change in color (3) the production of a gas (4) formation of a precipitate (solid coming out of solution)