Question

CH3CH2OH(g) −→ Cu(s) + CH3CHO(g) + H2(g)

A pure sample of ethanol, CH3CH2OH(g), is placed in a rigid, evacuated vessel with a copper catalyst at 227 C, where the CH3CH2OH(g) decomposes into CH3CHO(g) and H2(g) according to the equation above. The partial pressure of ethanol (PE) is initially 250. torr and decreases to 224 torr after 200 seconds and to 198 torr after 400 seconds. Which of the following graphs is consistent with the kinetics of the decomposition of CH3CH2OH(g)?

Answer 1

The decomposition of CH3CH2OH(g) as described shows a linear decrease in partial pressure over time, suggesting zero-order kinetics. The corresponding graph would depict a straight line with a negative slope, indicating a constant rate of reaction.

Step-by-step explanation:

To answer the question about what graph is consistent with the kinetics of the decomposition of CH3CH2OH(g), you need to consider how the partial pressure of ethanol decreases over time. Given that the partial pressure drops from 250 to 224 torr after 200 seconds and then to 198 torr after 400 seconds, we can see that the pressure decreases by a constant amount every 200 seconds. This implies a linear decrease in concentration over time, suggesting that the reaction is zero-order with respect to ethanol, since in a zero-order reaction, the rate is constant and independent of the concentration of the reactant.

A graph that shows a straight line with a negative slope, crossing the partial pressure axis at 250 torr and decreasing linearly over time, would be consistent with this observation. An example of such a graph would have 'Time' on the x-axis and 'Partial Pressure of Ethanol' on the y-axis, with the line starting at 250 torr at time zero and decreasing consistently as time increases.