All Flashcards
Define 'elementary reaction'.
A single-step reaction involving one or a few molecules.
What is an 'endothermic reaction'?
A reaction that absorbs energy from the surroundings; reactants + energy → products.
What is an 'exothermic reaction'?
A reaction that releases energy into the surroundings; reactants → products + energy.
Define 'activation energy (Ea)'.
The minimum energy required to start a reaction; the energy difference between reactants and the transition state.
What is the 'activated complex'?
The highest energy, most unstable point in a reaction; bonds are partially broken and formed.
Define the 'Arrhenius equation'.
The equation, , that describes how the rate constant of a reaction changes with temperature.
Label the axes of a potential energy diagram.
X-axis: Reaction Progress/Coordinate, Y-axis: Potential Energy.
On a potential energy diagram, what does the peak represent?
The peak represents the activated complex or transition state.
On a potential energy diagram, how do you identify ΔH for an exothermic reaction?
ΔH is the negative energy difference between the reactants and products.
On a potential energy diagram, how do you identify ΔH for an endothermic reaction?
ΔH is the positive energy difference between the reactants and products.
On a potential energy diagram, what represents the activation energy?
The energy difference between the reactants and the transition state.
What is the effect of increasing temperature on reaction rate?
Generally, an increase in temperature increases the reaction rate.
What is the effect of a catalyst on activation energy?
A catalyst lowers the activation energy.
What is the effect of higher activation energy on reaction rate?
Higher activation energy leads to a slower reaction rate.