Reaction rates, collision theory and measurable change
≈ 50 minReaction rates, collision theory and measurable change
Reaction rate measures how quickly reactants are used or products form. Collision theory explains that reacting particles must collide with sufficient energy to overcome activation energy and with suitable orientation; such collisions are effective. Temperature increases particle kinetic energy and collision frequency, concentration increases the number of particles per volume, surface area exposes more collision sites for solids, and catalysts provide an alternative lower-activation-energy pathway. A fair rate investigation changes one independent variable and measures a clear dependent quantity such as gas volume, mass loss, concentration or time to a fixed endpoint.
Work it through
If 0.60 mol of product forms uniformly in 30 s, average rate = 0.60/30 = 0.020 mol s⁻¹. A graph may start steep and flatten as reactants are used up, so rate is not always constant. The gradient at a point gives instantaneous rate, while a total change divided by time gives average rate over an interval.
Mastery target
Explain a rate change with collision theory, design a fair measurement and calculate average or interpret instantaneous rate with correct units.
Why does increasing temperature often increase reaction rate?
Name the key chemistry term from Reaction rates, collision theory and measurable change that best fits the explanation and visual model.
If 0.60 mol product forms in 30 s, what is the average rate in mol s⁻¹?
Which statement corrects a common misunderstanding in Reaction rates, collision theory and measurable change?