Chemical reactions can be represented symbolically using chemical equations. in a chemical equation, reactants appear to the left of the arrow, while products appear to the right. the law of conservation of mass states that matter is neither created nor destroyed in a chemical reaction; rather, the existing atoms are just rearranged. therefore, chemical equations must be balanced—that is, the same number of each kind of atom must be present before and after a chemical reaction.
an unbalanced chemical equation is shown below. balance the equation according to the law of conservation of mass.

Astudent completed a lab report. which correctly describes the difference between the “question” and “hypothesis” sections of her report? “question” states what she is asking, and “hypothesis” states the result of her experiment. “question” states what she is asking, and “hypothesis” states what she thinks the answer to that question is in “if . . then . . because” format. “question” describes what she is trying to find out, and "hypothesis" states the procedures and methods of data collection. “question” describes what she is trying to find out, and “hypothesis” states any additional information or prior knowledge about the question.