The term "3 fecl2" in a balanced equation says a) that there are three iron(ii) ions and two chloride ions bonded together. b) that there are three iron(ii) ions and 6 chloride ions bonded together. c) that there are three formula units, each consisting of two chloride ions bonded to an iron(ii) ion. d) that there are three particles, each consisting of three iron atoms and 6 chlorine atoms.

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.

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space

How are the terms group and period used on the periodic table