Changes that affect the from or shape of a substance, but not its chemical composition are called physical changes.
……………………. occur when a substance combines with another to from new substances.
Substances that undergo a chemical reaction are called ………….. . New substances which are the results of chemical reaction are called …………………… .
The ………….. states that matter is not created or destroyed.
An …………………….. allows matter to enter or escape from the system. The system in which the matter does not enter or leave is called a …………………….
In a chemical reaction, if overall reaction releases heat into the surroundings, the temperature falls, and the reaction is called …………………………….
The chemical reaction of a substance with oxygen is called ………………………….
A ………………….. is a substance that can increase the rate of a chemical reaction.
The ………………….. says that as more collisions in a system occur, atoms or molecules of that reactants will have a higher chance to complete the reaction.