Is it physical or chemical? page 135

Physical Change Any change in size, amount, shape, or state/phase of matter. nothing new is created Ex.) melting a block of ice, cutting a piece of paper in half (Skip 2-3 lines!)

Chemical Change substances change into new substances with different properties (= Chemical Reaction!) The original substance no longer exists Substances that undergo chemical change easily (like alkali metals) have a high reactivity Ex.) Digestion, spoiled food, explosives, and rust (Skip 2-3 lines)

To identify a change as Physical or Chemical, ask, “Did a Chemical Reaction occur?” If “no”  Physical Change If “yes”  Chemical Chemical ***How do we know if a chemical reaction occurred?

Physical or Chemical Change? Dissolving SaltDissolving Salt/ x1U

Physical or Chemical Change? Bleach and food dye a0Wo

Physical or Chemical Change? dry ice CO 2 goes from solid to gas – sublimation sublimation

Physical or Chemical Change? bending magnesium strip

Physical or Chemical Change? magnesium in HCl

Physical or Chemical Change? vinegar and steel wool = RustRust vinegar and steel wool = RustRust

Physical or Chemical Change? vinegar added to milk and the milk curdles

Physical or Chemical Change? bending magnesium strip