True or False. Chemical changes only rearrange the elements that are already present.

True or False. The reactants and the products of a chemical equation
always have the same number of atoms.

Compare and contrast physical changes with chemical changes.

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy

Consider the story you just read. all but one of the choices below indicate that something is living.