Unit 3 Flashcards
What is equilibirium
The point in a reversible reaction where there is no change in the concentration of products and reactants
- (Forward & Reverse processes occur at the same rate)
What occurs to the concentration and reaction rates after dynamic equilibrium is reached
Concentrations –> not changing (can be at different values)
Rates –> reactions in the forward/back are still occurring but at the same rate resulting in no change in concentration
What is the difference between static and dynamic equilibrium?
Static: Forward/Reverse reactions are not occurring + concentrations are not changing (bodies are at rest)
Dynamic: Concentrations are the same rate but reaction is occurring at the same rate (can occur)
Whats the difference between a closed & open system?
Closed: no matter is transferred, but energy is transferred
Open: Matter is transferred (reactants/products may be lost to the environment), energy can be transferred
What is an example of open system in chemistry, vs closed?
A pot of boiling water, where with a lid open, the water –> steam gets lost since gas moves away
Where lid is CLOSED –> the product (steam) cannot escape and condensates
What is the relation between closed and open system and dynamic equilbirium/static
Dynamic equilibrium can only occur in a CLOSED SYSTEM, because if it was open, the products could escape (if R–>P(gas)
Wheares static is usually open system here it escapes and then no rate change occurs between reactants and products
What is the collision theory
Particles can only react if they collide under the conditions of:
1. The minimum kinetic energy (or activation energy) is reached\
2. The correct orientation of the particle is reached
What occurs to collision if concentration decreases and why?
Lower concentration means less successful collisions due to less reactant particles exist to react to form products.
Define Le Chateliers Principle
For a system at dynamic equilibrium, if a change is made to the conditions of the reaction, the position of equilibrium with shift to counteract the change.
Where does equilibrium shift if the temperature of a system is increased, and why?
Shifts to the endothermic reaction
To absorb the extra heat, ultimately cooling down the reaction to counteract the increase
Where does equilibrium shift if the temperature of a system is decreased, and why?
Shifts to the exothermic reaction
By producing more heat and increase the temp again to counteract the decrease
How does collision theory relate to the increase in temperature at equilibrium
The reaction rate favours the side with the highest activation energy required to react (usually the endothermic) –> since the largest change
How does collision theory relate to the decrease in temperature at equilibrium
The reaction rate favours the side with the lowest activation energy required to react (usually the exothermic)
In 2No2(g) –>/<– N2O4(g) (-ve,change in H), Where does a increase in temperature favour
Favours the endothermic reaction thus the reactants. Since to counteract the temp increase, the reaction favours the side which absorbs the extra added heat (endothermic = left = reactants)
What occurs to the equilibrium of a system with an increase in the concentration of reactants and why?
A + B –>/<– C + D
Shifts equilibrium to the products
Le chattier, to counteract a change in conditions, wants to decrease concentration of reactants again by reacting them against each other and thus forming an increase in the concentration of products
What happens to the concentration of liquids/solids/gases with a increase in the amount of each?
LIQUID/SOLID
Cant have concentration at liquid and solid
Thus changing the amount of liquid/solid present does not affect the position of equilibrium
GAS
Increases concentration
What occurs to the equilibrium of a system with a decrease in the concentration of reactants and why?
A + B –>/<– C + D
Shifts equilibrium to the reactants
Le chattier, to counteract a change in conditions, wants to decrease concentration of products again by reacting them against each other and thus forming an increase in the concentration of reactants
What occurs to the equilibrium of a system with a decrease in the concentration of products and why?
A + B –>/<– C + D
Shifts equilibrium to the products
Le chattier, to counteract a change in conditions, wants to increase concentration of products again by reacting reactants, forming an increase in the concentration of products again while decrease in reactants (used)
What occurs to the equilibrium of a system with an increase in the concentration of products and why?
A + B –>/<– C + D
Shifts equilibrium to the reactants
Le chattier, to counteract a change in conditions, wants to increase concentration of reactants again by reacting products more forming an increase int he concentration of reactants again while decrease in products (used)
How does collision theory relate to the increase in the concentration of the products at equilibrium
Can be for both reactants/products
Increase in products shifts to the reactants. The rate of the backward (to reactants) increases as the reverse reaction is dominant, due to a higher proportion of product particles collided compared to reactant, ultimately resulting in higher successful product collisions and hence rate backwards is higher.
How does collision theory relate to the decrease in the concentration of the reactants at equilibrium
Can be for both reactants/products
Decrease in reactants shifts to the reactants. The rate of the backward (to reactants) increases as the reverse reaction is dominant, due to a higher proportion of product particles collided compared to reactant, ultimately resulting in higher successful product collisions and hence rate backwards is higher.
How does collision theory relate to the increase in the concentration of the reactants at equilibrium
Can be for both reactants/products
Increase in reactant concentration shifts to the products. The rate of the forward (to products) increases as the forward reaction is dominant, due to a higher proportion of reactant particles collided compared to product, ultimately resulting in higher successful reactant collisions and hence rate forward is higher.
What is the name of H3O+
Hydronium Ions
What is a hydronium ion
H3O+
What are the methods you can increase the pressure of a system (more gas in a smaller space)
- Pump more of the same gasses (at the same concentrations) into the system
- Decrease the volume of the system
- Add an inert gas (since it won’t react with anything)
All of which result in more gas in a smaller space
How much L does 1 mole of gas occupy
~ 24.79 (different for stuff)
What occurs to a reaction in dynamic equilbiriumwhen gas is added to the system
Pressure increases (Kpa), according to le chateliers, to counteract the change it needs to decrease the pressure of the system
–> shifts to the side with lower moles of gas (since if 2moles react to give 1 mole, less volume occupies)
What occurs to a reaction at dynamic equilibrium when the volume of a container is increased.
Pressure decreases (Kpa), according to le Chateliers, to counteract the change it needs to increase the pressure of the system.
–> shifts to the side with more moles of gas (since if 1 moles react to give 2 mole, more volume occupies)
What occurs to the rate of reaction, in relation to the collision theory as a result of the increase of inert gas within the system 2NO2(g) –>/<– 1N2O4(g)
Increases inert gas increases the Kpa pressure, le chatelier wants to decrease it by shifting to the side with less moles of gas (therfore shifts to forward reaction)
COLLISSION THEORY
Since 2:1 in gas moles, there is a increase in the reactant particles, more particles = more successful reactions thus a higher rate of reaction temporarily in reactants.
What does a grdual change in the concentration for all products and reactants indicate in a concentration/time graph?
A change in temp (undoes equilibrium to set a new one)
What does a spike in the concentration of 1 substance indicate in a concentration/time graph?
The increase/decrease in the concentration of a substance
What does a spike in all concentrations indicate in a concentration/time graph?
A change in pressure (increase/decrease in pressure due to a change in volume or inert gas added)
