Question

The rate of the reaction in terms of the "disappearance of reactant" includes the change in the concentration of the reactant, the time interval, and the coefficient of the reactant. Consider the following reaction: 2A+3B→3C+2D The concentrations of reactant A at three different time intervals are given. Use the following data to determine the average rate of reaction in terms of the disappearance of reactant A between time = 0 s and time = 20 s. Time (s) 0 20 40 [A](M) 0.1200 0.0720 0.0540 Express your answer in molar concentration per second to three significant figures.

Answer 1

The average rate of the reaction in terms of the disappearance of reactant A between time = 0 s and time = 20 s is -0.0024 M/s.

Step-by-step explanation:

The rate of a chemical reaction can be expressed as the change in concentration of a reactant over time. In this case, we are looking at the average rate of the reaction in terms of the disappearance of reactant A between time = 0 s and time = 20 s for the reaction 2A+3B→3C+2D. The concentrations of reactant A at three different time intervals are given: [A] = 0.1200 M at time = 0 s, [A] = 0.0720 M at time = 20 s, and [A] = 0.0540 M at time = 40 s. To calculate the average rate of reaction in terms of the disappearance of reactant A between time = 0 s and time = 20 s, we can use the formula:

Average rate = (change in concentration of A) / (change in time)

To calculate the change in concentration of A, we subtract the initial concentration from the final concentration: 0.0720 M - 0.1200 M = -0.0480 M. The change in time is simply 20 s. Plugging these values into the formula, we get:

Average rate = (-0.0480 M) / (20 s) = -0.0024 M/s

Therefore, the average rate of the reaction in terms of the disappearance of reactant A between time = 0 s and time = 20 s is -0.0024 M/s.

Answer 2

The average rate of the reaction is 1.2 × 10⁻³ M/s

Step-by-step explanation:

The rate of the reaction can be written in terms of the disappearance of reactant A. The average rate of the reaction is given by the variation of the concentration of reactant A over time divided by its stoichiometric coefficient:

average rate of reaction = - 1/2 * (final concentration - initial concentration)/time

Between 0 and 20 s, the average rate of the reaction is:

rate = - 1/2 ( 0.0720 M - 0.1200 M) / 20 s = 1.2 × 10⁻³ M/s