Balloon, why didn’t they react right away?

d. will an exothermic reaction increase or decrease the temperature?

go back to the simulator:
endothermic chemical reactions: click on the endothermic tab to begin.

7. before clicking the orange button to “break bonds.” how has the energy diagram changed? what is noticeable about the reactants in particular?

8. click the orange button to “break bonds,” then “make bonds,” and then “overall reaction.” based on the size of the arrows, is more energy absorbed to break bonds or released when bonds are formed?

9. the prefix “endo” means internal or within and the energy change in the reaction is positive, how does this relate to the endothermic chemical reaction that you just observed?

10. if you observed a chemical reaction take place in a container and the container got very cold, would this be an endothermic or an exothermic reaction?

11. comparing exothermic and endothermic reactions: when the sugars and carbohydrates formed by plants sit for millions of years they are rearranged into fossil fuels like coal, oil, and natural gas.
a. consider a combustion reaction of sugar:
c12h22o11 + 12o2 à 12co2 + 11h2o

just like burning fossil fuels, is this exothermic or endothermic?

b. consider photosynthesis to make sugar:

12co2 + 11h2o à c12h22o11 + 12o2

i. is this reaction exothermic or endothermic?

ii. in photosynthesis, where does the energy for the reaction come from?

c. how do you think the energy of the reaction in 11a compares to the energy of the reaction in 11 b?