Physical & Chemical Changes

Physical vs. Chemical Change Physical Change - Change that affects only the physical properties of a substance Physical properties include: Size, Shape and Phase of matter Appearance changes – not chemical makeup

Physical vs. Chemical Change Results from chemical reactions in which one or more new substances are formed End products are chemically different from the original. Corrosion-dissolving away metal-rusting.

Physical vs. Chemical Change Identify the following as physical or chemical change. Ice cube melting. People eating. Wood burning. Slicing an apple into pieces.

Changes in Matter - Continued Melting Point – Temperature at which a solid changes to a liquid Example: Ice  water Freezing Point – Temperature at which a liquid changes to a solid Example: Water  Ice (0°C)

Changes in Matter Boiling Point – Temperature at which a liquid changes into a gas Example: Water  vapor (100˚ C)

Changes in Matter - Continued Evaporation- process at which a liquid changes to a gas at boiling point Example: water boils to form steam

Changes in Matter - Continued Condensation – Process at which a gas becomes a liquid Gas cooled below its boiling point Example: water vapor  water, dew in the morning, glass of ice tea in hot weather.

Changes in Matter - Continued Sublimation – When a solid changes directly to a gas The matter doesn’t melt Example:snow, dry ice and glaciers Deposition- Gas changes directly into a solid

Changes in Matter - Continued Exotic Super Hot Nucleus of atom comes apart Particle accelerates Exotic Super Cold Below -270˚ C Superfluids from gases