Unit 1 Lecture 2: Physical and Chemical Changes The student is able to evaluate the classification of a process as a physical change, chemical change, or ambiguous change based on observation and understanding of covalent and non-covalent interactions.

Physical Property Characteristic that can be observed or measured without changing the identity of a sample (color, density, luster, covalent/ionic nature, etc.)

Chemical Property Ability of a sample to undergo changes that transforms it into a different substance (ability to rust, reactivity, ability to form a precipitate, etc)

Types of Properties Intensive – Does not depend on the amount of matter present Melting point, Boiling point, Density, Conductivity, Ability to transfer Energy as heat Extensive – Depends on the amount of matter present Volume, Mass, Amount of Energy in a Sample

Physical Change Change in a substance that does not change the identity of the substance Grind, cut, melt, boil, freeze, condense

Chemical Change Change in which one or more substances are converted into different substances Burn, Rot, Decompose, Ferment, Explode, Corrode

Clues that a Chemical Change has Occurred: Transfer of Energy Change in Color Gas Produced Precipitate Formed

Electrolyte Ionic compound whose aqueous solution and conducts electricity because it dissociates.

Demo Sugar and Salt Solutions pHet (Conductivity)

Exit Pass: Independently sort the examples into Physical or Chemical Changes.