A chemist is designing an experiment to investigate the effect of temperature on the rate of a piece copper oxidization. He records his data in his lab notebook. Which of the following answers contain the best (1) dependent,(2) independent, and (3) controlled variables that can exist in such an investigation? a
(1) temperature, (2) rate of copper oxidization, and (3) the initial mass of the copper piece
b
(1) rate of copper oxidization, (2) temperature, and (3) the initial mass of the copper piece
c
(1) the initial mass of the copper piece, (2) rate of copper oxidization, and (3) temperature
d
(1) temperature (2) the initial mass of the copper piece (3) rate of copper oxidization

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b.slope c.benchmark d. index contour

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

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.