Evidence of Chemical Reactions

Alter the size &/or shape Physical Changes Alter the size &/or shape Cut, grind, dissolve

Physical Changes Phase Changes

Easily changed back to original form Physical Changes Easily changed back to original form

Chemical Changes New stuff is made Cannot change new stuff back into original form easily Chemical composition of new substance is different from original

Hint- Can you turn cooked chicken back into raw chicken? Physical or Chemical? Hint- Can you turn cooked chicken back into raw chicken?

5 Evidences of Chemical Change Smell Change Color Change Energy change (hot, cold, light, sound, electricity, etc.) Bubbles, fizzing, gas produced Precipitate (2 clears make a cloudy)

Baked cupcakes smell differently than batter #1 Smell Change Baked cupcakes smell differently than batter

#2 Unexpected Color Change Colorless methane burns blue

As candle was burns, it gives off heat and light #3 Energy Change As candle was burns, it gives off heat and light

Evidence of a Chemical Reaction A gas evolves

Alka Seltzer in water makes carbon dioxide gas #4 Bubbles or Fizzing Alka Seltzer in water makes carbon dioxide gas

Evidence of a Chemical Reaction Precipitation – a solid is created.

Evidence of a Chemical Reaction Formation of water-

Evidence of a Chemical Reaction Changes in energy to the system It gets colder It gets hotter

SUMMARIZE Every reaction we did shows evidence of chemical change- what are 5? Please- Precipitate (2 clears make cloudy) Excuse- Energy change (heat, light, sound, electricity) Coughs- Color change (unexpected) Sneezes- Smell Change Burps- Bubbles or fizzing (gas produced)