You want to test how the mass of a reactant affects the speed of a reaction. Which of the following is an example of a controlled experiment to test this?
A. The mass of all the reactants is varied, and the time it takes the
reaction to finish is measured.
B. The mass of one reactant at a time is varied, and the time it takes
the reaction to finish is measured.
C. The mass of one reactant and the temperature of the reaction
mixture are increased until the reaction is finished.
D. The mass of all of the reactants is kept the same, and the mixtures
are allowed to react for different lengths of time.
SUBMIT

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.

What is the percent by mass of oxygen in fe2o3

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.