Changes in Matter

Physical Change Alters only the form or state of a substance (freezing, breaking, melting). No new substance is created. The chemical composition remains the same. It is usually reversible. The substance can usually return to the way it was before.

Types of Physical Change Types of Physical Change Examples: Change of State Dissolving Change of Form Ice Melting Mixing sugar in tea Chopping Wood

Changes in State

Changes of state Heat added or lost Two everyday examples (think of them as a class!) Freezing Lost   Condensation Vapourization Added Melting Sublimation (gas to solid) Sublimation (solid to gas)

Chemical Change Reactants → Products Changes a substance into a new substance that has different physical & chemical properties & a new chemical formula. Chemical changes are not usually reversible. The substance cannot be changed into what it was before. Chemical changes are the result of chemical reactions. Reactants → Products

Examples of a Chemical Change Cooking an egg A car rusting Burning wood Digesting food to produce energy

Signs that a chemical change has happened A permanent change in colour. Bubbles of gas are produced. Two solutions mix to form a solid called a precipitate. Energy in the form of heat or light is released or absorbed. Electricity is produced. The change is not easily reversed. **

Videos Characteristics of a Physical Change Video: https://www.youtube.com/watch?v=w4UjfZqo1M0 Chemical Change and Baking Video: https://www.youtube.com/watch?v=37pir0ej_SE

To Do / Homework 1. Physical vs. Chemical Changes Worksheets 2. Textbook: Read pages 157-158, 169 Questions: pg. 169 #3-5 3. Finish Density Column Assignment (due tomorrow!) 4. Review for Quiz – Physical and Chemical properties (including density) on Thursday!