To answer the questions,
(1) Activation energy is the amount of energy that is needed for the reaction to proceed, converting the reactant to products. The answer is letter B.
(2) The rate of chemical reaction normally increases as the reactant concentration is increased. The answer is letter C.
Answer:
A variable is anything that can change or be changed. In other words, it is any factor that can be manipulated, controlled for, or measured in an experiment.
Answer:
See explanation
Explanation:
Microwaves work by flipping water molecules upside down, then right side up again, and so on at very high speeds, and the friction generates heat. Some glass or plastic isn't affected by the microwaves, so the molecules don't get flipped, and so no friction occurs and no heat is produced, leading to the dish not being heated up.