Reaction Rate and Principles Flashcards
(31 cards)
What is reaction rate
- Change in quantity over change in time
- Speed of reactants converting to products
Three principles of collision theory
- Particles must collide
- Must collide with correct orientation
- Must collide with sufficient energy to achieve (Ea)
What is activated complex
- unstable complex
- formation of bonds
- old bonds weaken
- new bonds form
How does increase concentration affect Rx
- Concentration increases
- More particles per unit volume
- Frequency of collisions increase
- Frequency of successful collisions increase
- Rx increase
How does increase temperature affect Rx
- Temperature increase
- Average kinetic energy of particles increase
- Frequency of collisions increase
- Frequency of successful collisions increase
- Rx increase
How does increase surface area affect Rx
- Surface are increase
- number of particles exposed to reaction increase
- Frequency of collisions increase
- Frequency of successful collisions increase
- Rx increase
How does adding catalyst affect Rx
- Catalyst added
- Alternate pathway with lower (Ea) created
- Frequency of particles that can achieve the new lower (Ea) increase
- Frequency of collisions increase
- Frequency of successful collisions increase
- Rx increase
What is a open system
- Matter and energy free to be exchanged
- easy to monitor reaction progress
- can lead to contamination
What is a closed system
- Energy can be exchanged but matter cannot
- no contamination
- hard to monitor reaction progress
What is dynamic equilibrium
- Rate of forward and reverse reaction is equivalent
- Dynamic as reactions are constantly occurring
- Conc. of reactants and products constant
Requirements for dynamic equilibrium (2)
- Closed system
- Reversible reaction
What is a phase equilibrium
- physical process
- equilibrium achieved between two states of matter
What is Kc
- Equilibrium constant
- Products/Reactants
What substances can Kc be
- Gas and Aqueous
What is equilibrium position
Whether the forward or reverse reaction is favoured
How is equilibrium position formed
- Original equilibrium
- System is disturbed
- new equilibrium achieved
When is forward reaction favoured
- Rate of f.r > Rate of r.r
- Kc > 1
- Equilibrium position towards right
- [products] > [reactants]
When is reverse reaction favoured
- Rate of r.r > rate of f.r
- Kc < 1
- Equilibrium position towards left
- [products] < [reactants]
What is difference between Q and Kc
- Reactant quotient used when equilibrium not yet achieved
- Kc used at equilibrium
How does increase temperature affect endothermic reaction
- Temperature increase
- system wants to counteract
- absorbs energy
- forward reaction is favoured
How does decrease temperature affect endothermic reaction
- Temperature decrease
- system wants to counteract
- release energy
- reverse reaction is favoured
How does increase temperature affect exothermic reaction
Temperature decrease
- system wants to counteract
- release energy
- forward reaction is favoured
How does decrease temperature affect exothermic reaction
- Temperature increase
- system wants to counteract
- absorbs energy
- reverse reaction is favoured
Define exothermic in terms of bond breaking and forming
The energy of bond formation is greater than the energy of bond breaking
