Radioactive iodine, used to treat thyroid cancer, has a half-life of eight days. Find its decay constant, r.

Consider the equilibrium system: 2icl(s) ⇄ i2(s) + cl2(g) which of the following changes will increase the total amount of of cl2 that can be produced? all of the listed answers are correct decreasing the volume of the container removing the cl2 as it is formed adding more icl(s) removing some of the i2(s)

Which of these would be caused by a chemical change? a) the formation of lava. b) sedimantary rock layering over time. c) metamorphic rock forming from igneous. d) metamorphic rock eroding to form sedimentary rock.

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.