19. Classify the chemical reaction photosynthesis as ender- gonic or exergonic. Explain.
20. Explain why the total amount of energy does not decrease in an
exergonic chemical reaction.
3 21. Explain How can an endergonic reaction not be endothermic?
22. Classify the reaction that makes a firefly glow in terms of energy
input and output.
23. Think Critically To develop a product that warms people's hand
would you use an exothermic or endothermic reaction? Why?