Which of the following situations would cause the greatest decrease in the motion of molecules in a system?
a. q = -50 j, w = -50 j b. q = +50 j, w = +50 j c. q = -50 j, w = +50 j d. q = +50 j, w = -50 j

The answer is A. Q = -50 J, W = -50 J. A decrease in the motion of molecules in a system can be interpreted as a decrease or release in energy which means that energy should be negative. For the formula of energy:

U = Q + W

U is negative for the case of A. This gives the greatest decrease in the molecules' motion.

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