Explain the law of conservation of mass and give an example that demonstrates it.

Mass Cannot be created or destroyed. So everything that goes into a chemical reaction has to come out the other side, like cars driving into a tunnel. Any balanced equation of a chemical reaction is an example

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.