Physical and Chemical Changes Lesson 3 February 3rd, 2011

Physical Change In a physical change, the substance involved remains the same (chemically). The substance may change form or state, however. All changes of state are physical changes.

Physical Change Examples: Dissolving a substance in a liquid, breaking something. NOTE: Most physical changes can be reversed

Observing Chemical Properties (3) A chemical property describes the ability of a substance to change into a new substance or substances.

In order to view a chemical property a chemical change must occur. Chemical change - the formation of a new substance or substances with new properties. A chemical reaction is a process in which a chemical change occurs. Chemical properties include how a substance interacts with other substances

Chemical Properties 1. Combustibility is the ability of a substance to burn. In order to burn a substance requires Oxygen

Chemical Properties Light sensitivity is a chemical property of that can cause new substances to form when light hits it.

Chemical Properties 3. Reacting with an acid is a chemical property where when acid is poured on a substance it produces a gas and bubbles.

Clues that a chemical change has occurred Evidence of Chemical Change Example Picture Change in Colour Metal is silver- coloured; rusted metal is brown

Clues that a chemical change has occurred Evidence of Chemical Change Example Picture Bubbles appear or a gas is formed Sodium bicarbonate creates a gas when dropped in water.

Clues that a chemical change has occurred Evidence of Chemical Change Example Picture Heat or light is produced or absorbed A burning candle gives off light and heat

Clues that a chemical change has occurred Evidence of Chemical Change Example Picture A solid is formed Precipitate

Clues that a chemical change has occurred Evidence of Chemical Change Example Picture The change cannot be reversed A fried egg cannot be converted back to a raw egg.

WHMIS, HHPS, and MSDS labels provide information about what might happen when chemical changes occur. This information is intended to protect you.

Physical and Chemical Changes Worksheet Complete If time permits we will start the lab.