Curve X depicts the kinetic-energy distribution of NO₂(g) at 300 K
CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
Curve X depicts the kinetic-energy distribution of NO₂(g) at 300 K, and curve Y depicts the same sample at 320 K. Curve Y has a lower maximum height and its peak is displaced to a higher kinetic energy relative to curve X. A vertical line drawn to the right of both peaks marks the activation energy for NO₂ decomposition.
Which statement about the fraction of molecules able to decompose is most consistent with these curves?
(a) The fraction is larger for curve X because curve X has a higher peak height.
(b) The fraction is larger for curve Y because a greater area of curve Y lies to the right of the activation-energy line.
(c) The fractions are identical for both curves because the total area under each curve is the same.
(d) The fraction is smaller for curve Y because fewer molecules collide per unit time at higher temperature.