Name:_________________________________Date:__________________Class:____________________
Physical vs. Chemical Changes
In a physical change, the original substance still exists; it has only changed in form, so some of its
physical and chemical properties are still the same. In a chemical change (also known as a chemical
reaction,) a new substance is produced that has different chemical and physical properties from the
original susbtance. Energy changes always accompany chemical changes.
Classify the following as being a physical or chemical change.
1) Sodium hydroxide dissolves in water. ___________________________________
2) Hydrochloric acid reacts with potassium hydroxide to produce a salt, water and heat.
_____________________
3) A pellet of sodium is sliced in two. _____________________________
4) Water is heated and changed to steam.___________________________
5) Potassium chlorate decomposes to potassium chloride and oxygen gas. ____________________
6) Iron rusts. __________________________________
7) When places in H2O (water), a sodium pellet catches on fire as hydrogen gas (H2) is liberated and
sodium hydroxide forms. ___________________________________
8) Evaporation ___________________________
9) Ice melting ____________________________
10) Milk Sours ______________________________
11) Sugar dissolves in water.______________________________
12) Wood rotting _______________________________________
13) Pancakes cooking on a griddle _________________________________
14) Grass growing in a lawn ______________________________________
15) A tire is inflated with air. ______________________________________
16) Food is digested in the stomach. ___________________________________
17) Water is absorbed by a paper towel _____________________________________
18) A nail is hammered into a piece of wood _________________________________
19) An egg is boiled _________________________
20) Hair is dyed a new color _________________________
Adapted from Chemistry IF8766 © Instructional Fair, Inc. page 19