The rate of a chemical reaction is defined as the change in
Correct answer: A. concentration of a reactant or product per unit time
- A. concentration of a reactant or product per unit time
- B. temperature of the mixture per unit time
- C. mass of the catalyst per unit time
- D. total pressure of the system
Explanation
Rate measures how quickly reactants are consumed or products formed, so its units are usually moles per cubic decimetre per second. It is always positive, which is why a minus sign is written in front of the reactant term. Rate is greatest at the start, when reactant concentration is highest, and falls as the reaction proceeds.
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About Rate of Reaction
Reaction rate measures the change in concentration of a reactant or product per unit time. Questions connect rate with concentration, temperature, pressure, surface area, catalysts and nature of reactants, and may involve rate laws, reaction order, activation energy and collision theory. Rate describes speed, whereas equilibrium describes the final balance of opposing reactions.
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