Unit 7B Flashcards
(22 cards)
Reaction Rate
The changing of reactants to products (or the reverse) per unit of time
The Collision Theory
For an effective collision, particles must collide with enough kinetic energy and collide in the proper orientation
Activation energy
The minimum amount of energy required in order to get a reaction started
Endothermic
Reactions that require an input of energy to occur
Ex. Photosynthesis, plants must absorb sunlight
Reactants are at a lower energy than products
Exothermic
Reactions that release energy
Ex. All combustion reactions
Reactions are at a higher energy than products
Activated complex/transition state
Found at the peak of the energy diagram. Formed by the reactants where they have enough energy to form products OR go in the reverse direction and reform reactants
Forward reaction
When reactions convert to products
Reverse reaction
When products reform reactants
Reversible reaction
Can move in both forward and reverse direction
Temperature
Increasing temperature will increase reaction rate, and decreasing will decrease reaction rate
Increasing temperature increases particle and KE
Concentration
Increasing the number of particles increases number of particles and reaction rate
More particles will increase collision frequency
Particle size
The smaller the particles, the bigger the surface area. Bigger surface area=increase in rate of reaction
With more exposed area, there is an increased rate of reaction
Catalyst
Catalysts lower activation energy, therefore speeding up reaction rate
Reversible reaction
A reaction that can move in forward and reverse directions
Forward/reverse reaction
Forward: when reactants convert to products
Reverse: when products convert to reactants
Chemical equilibrium
the state in which the forward and reverse reations take place at the same rate
Product favored
when there is more formation of products
Reactant favored
when there is more formation of reactants
Reaction rates
Catalyst
Catalysts speed up the reaction rate
Do not affect the concentration of reactants or products
Decrease the time it takes to establish equilibrium
Le Châtlier’s Principle
When stress is applied to a system at equilibrium, the equilibrium will shift in order to relieve the stress
Equilibrium: Temperature
Increasingthe temperature causes the equilibrium to shift in the direction that absorbs the headt
Equilibrium: Pressure
Pressure will shift in the direction with the least amount of molecules of gas
