Endothermic And Exothermic Reactions

Question 1

What is energy?

Answer 1

Think of energy as stuff you’re able to do when you feel “energetic”
Example: speed, height,sound, heat, light.
2. Or as where you get this “energetic “ feeling from…
Example: calories (food)

Question 2

physical change

Answer 2

A physical change does not alter the chemical formula of a substance.
All physical changes involve energy

Question 3

Chemical change

Answer 3

A chemical change (aka chemical reaction) does alter the chemical formula of a substance.
All chemical changes involve energy.

Question 4

When a chemical reaction takes place… what is the “system” and what is the “surroundings”?

Answer 4

1.The “system” is the chemical involved in the reaction (reactants and products )
2. The “surroundings” is everything else in the universe.

Question 5

What does the Law of Conservation of Energy say?

Answer 5

Energy cannot be created or destroyed.
Therefore … energy that leaves the system must go to the surroundings (and vice versa)

Question 6

Most reactions have an activation energy. This is because…

Answer 6

Breaking bonds require energy and forming bonds releases energy