Equilibrium

Question 1

What is chemical equilibrium/

Answer 1

The stage where the quantities of reactants and products in the reaction remain unchanged

Question 2

Why is equilibrium important in industry?

Answer 2

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)

Question 3

What is the dynamic state of equilibrium?

Answer 3

Where the forward and backward reactions have not ceased but occur simultaneously at the same rate

Question 4

What remains constant during dynamic equilibrium?

Answer 4

• The amounts and concentrations of chemical substances (also in chemical equilibrium)
• pressure
• temperature
• reaction is incomplete

Question 5

For K values in two equations being added together

Answer 5

K is multiplied

Question 6

For values for k that are 10^-4 to 10^4

Answer 6

There will be a significant amounts of reactants and products present at equilibrium

Question 7

K greater than 10^4

Answer 7

The equilibrium mixture consist mostly of products, with relatively small amounts of reactants. System favours products (profitable)

Question 8

K less that 10^-4

Answer 8

The eqm mixture consist mostly of reactants with relatively small amounts of products. System favours reactants (loss)

Question 9

Define Le chateliers principle

Answer 9

If an eqm system is subject to a change, the system will adjust itself to partially oppose the effect of the change

Question 10

What factors can change the position of eqm

Answer 10

• Adding or removing products or reactants
• Changing the pressure by changing the volume (gases)
• Dilution (solution)
• Changing temperature

Question 11

Addition or removal of a reactant or product

Answer 11

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.

Question 12

Change of temperature

Answer 12

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

Question 13

Change volume of the container

Answer 13

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

Question 14

Increase pressure but mols on either side of reaction are the same

Answer 14

LCP predicts that the system will try to decrease the pressure. However neither reaction will decrease the number of products.

Question 15

Adding some insert gas

Answer 15

Concentrations of reactants and products will not change, no change to eqm

Question 16

Why does increasing the temperature increase the rate of the endothermic reaction?

Answer 16

Reactions with a higher activation energy are more sensitive to an increase in temperature than those with a lower Ea

Question 17

How does a catalyst change the rate of reaction?

Answer 17

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.

Question 18

Inert gas and rate of reaction

Answer 18

Pressure of the inert fas in the eqm mixture decreases the likelihood of collisions between reactant molecules therefore decreasing rate of reaction.

Question 19

Oxygen transport equation

Answer 19

haemoglobin + oxygen oxyhaemoglobin

Question 20

Explain LCP and oxygen transport

Answer 20

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

Question 21

CO equation

Answer 21

haemoglobin + carbon monoxide carbon monoxide haemoglobin

Question 22

Explain competing equilibria

Answer 22

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

Question 23

Treatment of carbon monoxide poisoning

Answer 23

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.

Question 24

Percentage atom economy

Answer 24

Mr of desired products / mr total reactants