Studied by 10 peopleReaction rate
measurement of the change in moles of a reactant over time
Collision Theory
chemical reactions take place when molecules collide, provided that they
Have enough kinetic energy
Face the right way when they hit
Reaction curve/potential energy curve
either endothermic or exothermic, show the energy needed to break bonds and form bonds
+ΔH, more energy required to break bonds, less to from, feel cold, reactants have lower energy than products
Endothermic
-ΔH, less energy to break bonds, more to form, feel warm, reactants have higher energy than products
Exothermic
Endothermic graph
Exothermic graph
absorbs energy
breaks bonds
releases energy
forms bonds
final energy - initial energy
ΔH
Reversible
Reactions are ___________
Catalyst
speeds up a reaction by lowering activation barrier of a reaction
Inhibitor
slow down a reaction by raising the activation energy
Reversible reactions
reaction occurs both in the forward and reverse direction. As fast as products are being made, they are reverting back into reactants
Equilibrium
the concentration of the products and reactants do not change. The rate of the forward reactions is equal to the rate of the reverse reactions
Chemical equilibrium
as fast as reactants are being made, they are reverting back to reactants
Le Chatelier’s Principles
if stress is applied to a system in equilibrium, the system changes to relieve stress
Temperature
Concentration
Pressure
Stresses that change equilibrium
More is added to reactants, the reaction shifts to the products
More is added to products, the reaction shifts to the reactants
Decrease reactants, reaction shifts toward reactants
Decrease products, reaction shifts toward products
Effects of changing concentration
Adding heat shifts reaction to the reactants
Taking away hear shifts reaction to the products
Affect of Temperature
heat + AB + C ⇌ AC + B
Endothermic reaction and heat
AB + C ⇌ AC + B + heat
Exothermic reaction and heat
Only affects gases (reactants that have an unequal amount of gases in products and reactants). If pressure is increased, the reaction shifts to the reactants
Affects of pressure
Equilibrium constant
the ratio of the product concentrations to the reactant concentrations at equilibrium ([ ]). Tells us the concentration of reactants and products
Spontaneous reaactions
exothermic, low activation energy, can occur quickly, slowly, occur naturally, favor products at equilibrium, release energy. Can occur by themselves and do not need outside energy put into a system
Free energy
amount of heat released from a reaction
entropy
disorder of a system
Law of disorder
states that all systems tend to move toward maximum disorder of randomness
Non spontaneous reactions
do not give a substantial amount of products at equilibrium. Need outside energy to begin
entropy; temperature
________ increases as _______ increases
Note
Flashcard