The appropriate dimensional unit for the rate of a chemical reaction is_________________?
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Answer: A. Moles dm-3 sec-1
Explanation
Reaction rate is expressed as the change in concentration per unit time, yielding the standard SI unit of moles dm-3 sec-1. Dividing the change in molarity by the elapsed time interval directly produces this specific dimensional unit. Dimensional analysis confirms that concentration divided by time accurately describes the speed of a chemical transformation. Reaction kinetics studies the speeds at which chemical reactants are converted into products over time. Concentration is commonly measured in moles per cubic decimeter, which is identical to molarity units. Time intervals in kinetic rate expressions are typically recorded in standard seconds for consistency.
Option B describes simple molar concentration without accounting for the time elapsed during the reaction process. Option C omits the volume dimension entirely, representing only moles per second instead of concentration change. Option D inverts the concentration term incorrectly and does not match standard kinetic rate dimensions.
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