2.3 Energy Changes During Chemical Reactions
Book for Endothermic and Exothermic Reactions.
Endothermic Reactions
There is a net requirement or absorption of energy in some chemical reactions. The bond breaking process in the reactants requires more energy than is released in total. Energy from an external source must be absorbed.
energy + Reactants ? Products
Such reactions which absorb energy are called endothermic reactions. ("Endo" means "into.")
Plants have the ability to use the sun's energy to convert carbon dioxide and water into glucose and oxygen. This is the opposite process of cellular respiration and is called photosynthesis:
6 CO2(g) + 6 H2O(l) + 2803 kJ (from the sun) ? C6H12O6(s) + 6 O2(g)