Endothermic vs. Exothermic Reactions
All chemical reactions involve ​energy​. How is energy used in chemical reactions? (2 ways)
Take notes on the three articles and three videos you have been assigned to watch. List at least
5 characteristics of an exothermic reaction and 5 characteristics of an endothermic reaction.
Endothermic Reactions
Exothermic Reactions
Energy is released or absorbed as heat. 𝚫H means change in heat. (𝚫=the capital Greek letter
delta, which in chemistry means “change”
1. In which diagram (energy curve) do the products have more energy than the reactants?
2. In which diagram (energy curve) do the reactants have more energy than the products?
3. In which energy curve has energy (heat) been absorbed?
4. In which energy curve has energy (heat) been absorbed?
5. Label each energy diagram as endothermic or exothermic.
6. IN YOUR OWN WORDS, describe how an instant cold pack works? Is it exothermic or
endothermic? Why?
7. What does the law of conservation of energy state?
8.
In the above diagram, where is the system, and where are the surroundings?
9. How do the system and the surroundings relate in terms of energy?
10. Run the simulations (1st video) in the 3rd article. Click the box to turn the ion labels on.
a. What happens to the ions when they mix with water?
b. Which compounds cause an endothermic reaction, and which chemicals cause
an exothermic reaction? How do you know?
11. According to Tyler DeWitt (3rd video, 3rd article) what should you think about when
determining whether a reaction is exothermic or endothermic?