Chapter 5 Flashcards
(16 cards)
Define rate of reaction.
Change in concentration of reactant or product per unit time.
What factors affect reaction rate?
Concentration, temperature, surface area, catalysts, pressure (for gases).
Explain how increasing temperature increases reaction rate.
More particles have energy ≥ activation energy; collisions more frequent and energetic.
Explain how increasing concentration increases reaction rate.
More particles in same volume; collisions more frequent.
How does surface area affect reaction rate?
Increasing surface area exposes more particles to react, increasing collision frequency.
What is a catalyst?
Substance that increases rate of reaction by providing an alternative pathway with lower activation energy, without being used up.
Define activation energy (Ea).
Minimum energy particles need to react successfully.
What is a reaction mechanism?
Stepwise sequence of elementary reactions by which overall reaction occurs.
What is the rate-determining step?
Slowest step in a reaction mechanism, controlling overall rate.
How do you determine rate equation from experimental data?
By observing how rate changes with concentration changes of reactants.
What is the order of reaction?
Power to which concentration of a reactant is raised in the rate equation.
What does zero order mean?
Rate does not depend on concentration of that reactant.
What does first order mean?
Rate is directly proportional to concentration of that reactant.
What does second order mean?
Rate is proportional to the square of concentration of that reactant.
Explain how to use initial rates method to find rate equation.
Measure initial rates at varying reactant concentrations and deduce orders from how rates change.
Describe how a catalyst affects the reaction energy profile.
Lowers activation energy peak, increasing rate.
