3.1.6 chemical equilibria (just things dont know )

Question 1

in a reversible reaction at equilibrium

Answer 1

• the forward + reverse reactions proceed at equal rates
• the concentrations of reactants and products remain constant

Question 2

dynamic equilibrium

Answer 2

the point where the forward and backward reaction are happening at the same rate , the conc of reactants and products is constant and this can only happen in a closed system

Question 3

closed system

Answer 3

on in which none of the reactants or products escape from the rxn mixture

Question 4

open system

Answer 4

matter and energy can be lost to the surroundings

Question 5

homogenous system

Answer 5

system where all the chemicals are in the same place

Question 6

le chateliers principle

Answer 6

if a system at equilibrium is disrupted , the position of equilibrium will shift in the direction that counteracts / lessens the effect of change

Question 7

effect of increasing temp

Answer 7

• equilibrium shifts to favour the endothermic reaction
• as the excess heat needs to be removed from the system to counteract / lessen the effect of the initial increase
• it will increase the yield of the endothermic products

Question 8

effect of decreasing temp

Answer 8

• equilibrium shifts to favour the exothermic reaction
• as heat needs to be gained to counteract / lessen the effect of reduced temperature and an exothermic reaction releases heat
• it will increase the yield of the exothermic products

Question 9

effect of increase in conc of reactants

Answer 9

• equilibrium shifts to favour the reaction that produces / moves right
• to get rid of the extra reaction by forming more product as more molecules are available to react
• it will increase the yield of the products

Question 10

effect of decrease in concentration of reactants

Answer 10

• equilibrium shifts to favour the reaction that produced reactants / moves left
• to counteract the effect of less reactants
• it will increase the yield / concentration of the reactants

Question 11

effect of increasing pressure

Answer 11

• equilibriums shifts to favour the side with fewer moles
• this will help to release the build up in pressure and decrease the pressure
• it will increase the yield of the products on this side of the rxn

Question 12

effect of decreasing pressure

Answer 12

• equilibrium shifts to favour the side with more moles
• pressure has been lost
• the yield of the products on this side of the rxn will be increased

Question 13

equilibriums rxns in industry

Answer 13

• in industry they remove the products so that equilibrium shifts to right so more yield of products is made
• a compromise is made as a low temp gives food yield but slow rate , high temp would have faster rate of rxn . so a compromise is made
• a high pressure would be ideal as equilibrium would shift to the product side however it’s expensive

Question 14

dynamic graphs

Question 15

if Kc is large / greater than 1

Answer 15

equilibrium lies to the right as product concentration is greater than reactant concentration

Question 16

if Kc is small / less than 1

Answer 16

equilibrium lies to the left as reactant conc is greater than product conc

Question 17

if Kc is greater than 10^10

Answer 17

reaction is going to completion

Question 18

effect on kc if more reactants (result of change in temp)

Answer 18

Kc decreases as in equation reactants are on the bottom and a larger denominator results in a lower Kc

Question 19

effect on kc if more products (result of change in temp)

Answer 19

Kc increased as in equation products are on the top and a larger numerator results in a higher Kc

Question 20

exothermic rxn

Answer 20

increase in temp = Kc decreases as equilibrium shifts in endo direction
decrease in temp = Kc increases as equilibrium shifts in exo direction

Question 21

endothermic rxn

Answer 21

increase in temp = Kc increases as equilibrium shifts in endo direction
decrease in temp = Kc decreases as equilibrium shifts in exo direction

Question 22

equilibrium law