Thursday September 20, 2012 (Categories and Properties of Matter)

A _________ property of matter is one that does not change the identity of the material if it is observed or measured. Melting, freezing, evaporation, condensation, cutting, tearing and breaking are examples. By contrast, a _________ property of matter is one that changes the identity of the material if it is manipulated. Rusting, digesting, and burning are examples. Bell Ringer Thursday, physical chemical

An _________ property is a physical property of matter that does not depend on the amount of matter in a sample. For example, density is an intensive property of a substance because it does not depend on the amount of that substance that you have. Whether you have a small piece of copper or a very large chunk, copper always has a density of 8.63 g/cm 3. By contrast, an _________ property is a physical property of matter that does depend on the amount of matter in a sample. It is directly proportional to the amount of material in the sample. For example, both mass and volume are extensive properties. Obviously, the larger the sample of iron you have, the greater its mass and its volume. Bell Ringer Thursday, intensive extensive

Announcements None today

Assignment Currently Open Summative or Formative? Date IssuedDate Due Date Into GradeSpeed Final Day QUIZ 2S29/7 9/21 WS – Density = mass / volume F99/109/13 Lab – The Rainbow LabF109/119/12 Lab – Density of MetalsF119/139/14 QUIZ 3S39/14 9/28 Quiz – Science Lab Safety S49/17 WS – Categories, Properties, and Phases of Matter F129/179/21 Quiz – Matter Vocabulary S59/18

Categories of Matter

Determining Categories of Matter Can it be separated physically? NoYes Can it be separated chemically? No Yes Is it evenly mixed? Yes No

The Least You Need to Know Physical properties of matter are those that, when manipulated, observed, or measured, do not change the chemical identity of the matter sample.

Physical Property - Melting

Physical Properties – Evaporation and Boiling

Physical Property - Freezing

Physical Property - Condensation

The Least You Need to Know Chemical properties of matter are those that, when manipulated, change the chemical identity of the matter sample into new substances.

Chemical Property - Rusting The element iron "rusts" when it reacts with oxygen of the air, usually in the presence of water, to form a brown substance known as iron oxide. It is a slow chemical reaction which takes place over a period of time. Rust is the common name for iron oxide.

Chemical Property - Tarnishing The presence of the compound hydrogen s sulfide (H 2 S) in any material that silver comes into contact with is one of the prime reasons for silver tarnish. Materials like wool, rubber bands, fuels derived from fossils, a few types of paints and rubber (latex) gloves are some of the common materials that cause tarnishing of silver.. Certain foods like eggs and onions also hasten the silver tarnish process. You can therefore realize that touching silver jewelry with oily hands or after a meal could also stain your silver jewelry with tarnish. The extent and speed with which your silver jewelry tarnishes is also related to the climate and in general, high humidity would result in silver tarnishing much faster.

Chemical Property - Oxidization