4.2.5 Journal: Reactions Around You List 10 chemical reactions that have benefited your life today. Include the reasons you think each was indeed a chemical reaction and not just a physical change. (20 points) Think about processes in your body, processes in the atmosphere, or chemical reactions that may be involved with any materials or products you have used.

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Which of these statements explains the difference between nuclear binding energy and the strong nuclear force ?

Enzymes affect the reactions in living cells by changing the