Chapter 5 Flashcards
Combination Reaction
Two molecules come together to form an intermediate that decomposes to produce two final products
Rate-determining Step
Slowest step of a reaction
* Determines overall rate of reaction
* Reaction can only proceed as fast as rate-determining step
Activation Energy
Minimum energy needed for a chemical reaction to occur
* Distance on y-axis from energy of reactants to peak energy before formation of products
* Lowest activation energy = fastest rate of reaction
Transition State Theory
Focuses on forming high-energy activated complex that can then proceed forward/backward, forming products or reverting to reactants
- Requires certain activation energy to be overcome for a reaction to occur
Collision Theory
Focuses on energy and orientation of reactants and considers each potential reaction to be all-or-nothing (either enough energy to form products or not)
- Requires certain activation energy to be overcome for a reaction to occur
Zero-Order Reaction
Have constant rate that doesn’t depend on concentation of reactant
- Temperature lowered: rate decreased
- All reactants’ concentrations doubled: rate unaffected
- Catlyst added: rate increased
First-Order Reaction
Has a nonconstant rate that depends on concentration of reactant
* Temperature lowered: rate decreased
* All reactants’ concentrations doubled: rate doubled
* Catalyst added: rate increased
Second-Order Reaction
Has nonconstant rate that depends on concentration of reactant
* Temperature lowered: rate decreased
* All reactants’ concentrations doubled: rate multiplied by 4
* Catalyst added: rate increased
Endothermic
Exothermic
Spontaneous Reaction (Exergonic)
Net free energy change is negative
Nonspotaneous (Endergonic) Reaction
Net free energy change is positive
Rate of Reaction
- Temperature directly affects rate constant
- Changing partial pressure of gas will affect number of effective collisions per time
- Solvents affect rate of reactions depending on reaction solvent interaction
Saturated Catalyst
- Have maximum turnover rate
- Can’t increase rate constant or reaction rate any higher by adding more reactant
Catalyst
Increases the rate of reaction by lowering the activation energy making it easier for both forward and reverse reactions to overcome energy barrier
* Not used up
* Don’t alter equilibrium of reaction
* Stabilize transition state by lowering energy, not raising or eliminating