MATTER: IT TAKES UP SPACE AND HAS MASS Chapter 3 Matter: Properties and Changes Sections 3.1 and 3.2

Physical Properties of Matter Extensive properties… depend on the amount of substance. true-wildlife.blogspot.com Mass Length

Volume

Intensive properties are… independent of the amount of matter. Density

Other intensive properties: Color Hardness Odor Melting point Boiling point

Physical Changes… Type of Change Reversible Irreversible Example Dissolving a substance in water and then evaporating the water. Ripping a piece of paper cracking an egg.

Examples or Reversible or Irreversible?

How we get phase changes… Melting pointBoiling point Are these extensive or intensive properties?

Chemical Properties of Matter Ability or inability of a substance to change into one or more different substances. Original matter can NOT be recovered A new thing is made Also called a chemical reaction

Examples

Evidence of a Chemical Change Evidence that a chemical change may may have occurred:  Change in temperature  Change in color  Odor  Gas bubbles  Appearance of a solid

In this activity, soaking the penny in the zinc solution actually coated the surface of the penny with zinc atoms. When the zinc covered penny was heated, the copper atoms of the penny and the zinc atoms coating the penny mixed and turned gold in color. This mixing of metals is an alloy called “yellow brass.” CuZn Brass Is this an extensive or intensive change?

Placing copper, or a copper-coated penny, in a mixture of zinc metal and aqueous zinc chloride causes zinc metal to plate out on the copper surface. This reaction occurs due to electrochemical potential differences that result when different “forms” of zinc solid are contained in a solution of 1M ZnCl2. The driving force in this reaction is formation of a brass alloy on the surface of the copper. Zn2+(aq) + 2e– → ZnCu (alloy) Note: ZnZn = zinc that deposits on the granular zinc ZnZn → Zn2+(aq) + 2e– ZnCu = zinc that deposits on the copper ZnZn → ZnCu E = +1.0 V