Equilibrium Flashcards
What is chemical equilibrium/
The stage where the quantities of reactants and products in the reaction remain unchanged
Why is equilibrium important in industry?
The presence of large amounts of unreacted starting materials in reaction mixtures is wasteful and costly. The profitability of the industry is dependent upon the event of conversion of reactants into products (how far the reaction will go)
What is the dynamic state of equilibrium?
Where the forward and backward reactions have not ceased but occur simultaneously at the same rate
What remains constant during dynamic equilibrium?
- The amounts and concentrations of chemical substances (also in chemical equilibrium)
- pressure
- temperature
- reaction is incomplete
For K values in two equations being added together
K is multiplied
For values for k that are 10^-4 to 10^4
There will be a significant amounts of reactants and products present at equilibrium
K greater than 10^4
The equilibrium mixture consist mostly of products, with relatively small amounts of reactants. System favours products (profitable)
K less that 10^-4
The eqm mixture consist mostly of reactants with relatively small amounts of products. System favours reactants (loss)
Define Le chateliers principle
If an eqm system is subject to a change, the system will adjust itself to partially oppose the effect of the change
What factors can change the position of eqm
- Adding or removing products or reactants
- Changing the pressure by changing the volume (gases)
- Dilution (solution)
- Changing temperature
Addition or removal of a reactant or product
Adding extra reactant, LCP predicts that the system will try to remove the extra product by favouring the forward reaction. Position of eqm will shift to the right.
Change of temperature
Increase temperature: LCP predicts that the system will try to decrease the temperature by favouring the (..) direction. For this equation this is the backwards reaction. Position of eqm will shift to the left
Change volume of the container
Increase volume, LCP predicts that the system will try to increase the pressure by favouring the (..) reaction because this reaction results in an increased mole of gas. Position of eqm will shift to the left
Increase pressure but mols on either side of reaction are the same
LCP predicts that the system will try to decrease the pressure. However neither reaction will decrease the number of products.
Adding some insert gas
Concentrations of reactants and products will not change, no change to eqm
Why does increasing the temperature increase the rate of the endothermic reaction?
Reactions with a higher activation energy are more sensitive to an increase in temperature than those with a lower Ea
How does a catalyst change the rate of reaction?
Rate of forward reaction and backward increase simultaneously. A catalyst can help establish eqm faster but it has no effect on the equilibrium constant or equilibrium concentrations for eh reacting species. No net shifts.
Inert gas and rate of reaction
Pressure of the inert fas in the eqm mixture decreases the likelihood of collisions between reactant molecules therefore decreasing rate of reaction.
Oxygen transport equation
haemoglobin + oxygen oxyhaemoglobin
Explain LCP and oxygen transport
Using LCP, relatively high concentrations of O2 will cause a net forward reaction
- Most haemoglobin is converted to oxyhemoglobin the lungs (partially oppose)
- Oxyhaemoglobin is transported to the tissues through the blood circulatory system
- In the tissues the concentration of O2 is low and the backward reaction occurs, releasing O2 for use by cells
CO equation
haemoglobin + carbon monoxide carbon monoxide haemoglobin
Explain competing equilibria
The reactions of haemoglobin with O2 and CO are competing equilibria, since both the O2 and CO compete for haemoglobin
-THe equilibrium K has a significant effect of the position of equilibrium of these reaction. K value for the CO reaction is very high than the K value for the O2. That means with even a small concentration of CO causes position of eqm to go well to the right
Treatment of carbon monoxide poisoning
Due to huge value of K for the CO reaction, even with a low concentration of CO the following reaction will shift right. Deplete the O2 from the HbO2 complex
HbO2 + CO HbCo +)2
According to LCP to partially oppose the effect, net backward reaction occurs with high concentration of O2 in air, introduced into the lungs continuously. This causes [Hb] in blood to drop and HbCO complex to break, removing CO.
Percentage atom economy
Mr of desired products / mr total reactants
