collision theory Flashcards
(18 cards)
What must occur for a chemical reaction to take place?
Particles must collide
Not all collisions result in reactions; they must have correct orientation and sufficient energy.
What is activation energy?
Minimum kinetic energy required for a reaction to happen
It determines whether a reaction is spontaneous or nonspontaneous.
How does temperature affect activation energy?
Higher temperature increases the likelihood of reaching activation energy
It enhances the kinetic energy of particles.
What is the relationship between enthalpy and activation energy?
Enthalpy value remains the same for forward and reverse reactions, while activation energy differs
Exothermic reactions require lesser activation energy.
Define the term ‘transition state.’
The state of chemicals at the peak of a potential energy diagram
It is also known as the activated complex.
What characterizes an activated complex?
It is unstable, high energy, and contains partial products being formed
It is neither a reactant nor a product.
What factors affect the rate of a chemical reaction?
- Concentration
- Surface area
- Temperature
- Nature of reaction
- Catalyst
Each factor influences the frequency and effectiveness of collisions.
How does concentration affect reaction rate?
Lower concentration leads to fewer collisions per unit of time
Fewer effective collisions are likely to occur.
What impact does surface area have on reaction rates?
Smaller surface area results in fewer surfaces for collisions to occur
This leads to reduced effective collisions.
How does temperature influence kinetic energy in reactions?
Lower kinetic energy results in fewer frequent and effective collisions
Higher temperature increases collision energy.
What is the Maxwell-Boltzmann distribution?
It describes the distribution of energies among particles in a system
Only some particles have sufficient energy (Ea) for a reaction.
How does the nature of reactants affect reaction rates?
Homogeneous reactants react faster than heterogeneous due to greater collision opportunities
Factors include state of matter, molecular size, bond type, and bond strength.
What role does a catalyst play in a chemical reaction?
It provides an alternate pathway for the reaction and lowers activation energy
This increases the proportion of molecules that can reach activation energy.
What distinguishes a homogeneous catalyst from a heterogeneous catalyst?
Homogeneous catalysts are in the same state as the reactants, while heterogeneous catalysts are in a different state
Most catalysts are gaseous or aqueous.
True or False: Activation energy is dependent on temperature.
False
Activation energy remains constant regardless of temperature.
Fill in the blank: A catalyst ______ activation energy.
lowers
This allows reactions to proceed with less energy.
What is the effect of inhibitors on reaction rates?
They increase the rate of reaction by blocking the active site and increasing activation energy
Inhibitors hinder the reaction process.
How does bond strength affect reaction speed?
Weaker bonds break more easily, leading to faster reactions
Stronger bonds require more energy to break.
