Classify each of the following as chemical and physical change
Paper burns
Food digest
ice melts
silver tarnish
glass breaks
baking bread
water evaporates
dead leaves decaying
Physical Change
Chemical Change
Imagine that you break a a glass cup. Has a new substance been formed?
Breaking a glass cup is a ......
Is NaCl (table salt) dissolving in water a physical or a chemical change?
You may have been told that a chemical change is something you can't undo, but a physical change is something you can undo. That isn't really true, but it is a decent rule of thumb. The better definition is: