u2: dynamic equilibrium

Question 1

when’s dynamic equilibrium

Answer 1

• forward and reverse processes occurring at same rate

Question 2

what does dynamic equilibrium require?

Answer 2

• two opposing processes
• for chem rxns: fwd and reverse reaction

Question 3

real life examples of dynamic equilibrium

Answer 3

• running up a down escalator
• ## swimming pool suctions

Question 4

what kind of system does dynamic equilibrium take place in?

Answer 4

• closed system
• if rxn forms products that can escape, then reverse rxn can’t occur bc products are unavailable

Question 5

irreversible reaction graph shape

Answer 5

cross and then reactants go to zero, products go up

Question 6

reversible reaction graph shape

Answer 6

both go towards flatline that isn’t zero

Question 7

characteristics of equilibrium reactions

Answer 7

1. fwd rxn rate same as reverse rxn rate
2. macroscopic changes don’t occur
3. microscopic changes occur (collision theory)
4. same equilibrium attained even if rxn starts with excess of reactants or products
5. temperature impacts equilibrium

Question 8

what is important to examine equlibrium?

Answer 8

macroscopic qualities must be constant (temp, pressure, concentration, colour, pH)

Question 9

types of equilibrium

Answer 9

• solubility equilibrium
• phase equilibrium
• chemical reaction equilibrium

Question 10

solubility equilibrium

Answer 10

• dynamic equilibrium between solute and solvent in saturated solution (closed system)
• e.g. salt in water

Question 11

phase equilibrium

Answer 11

• dynamic equilibrium between diff. physical states of pure substance (closed system)
• e.g. melting/freezing water

Question 12

chemical reaction equilibrium

Answer 12

• dynamic equilibrium between reactants and products of chem rxn (closed system)

Question 13

law of chemical equilibrium/law of mass action

Answer 13

there is a constant ratio between concentration of products and of reactants

Question 14

equilibrium constant

Answer 14

• relationship between concentrations of prod. and reacts. at equilibrium at a specific temperature
• ratio between the rate constant for fwd rxn and rate constant for reverse rxn

Question 15

homogenous vs heterogenous equilibria

Answer 15

• homogenous equilibria: all have same state
• heterogenous equilibria: diff. physical states

Question 16

wht are removed from equilibrium constant expression? why?

Answer 16

• pure solids and liquids
• bc. they have constant concentration

Question 17

Keq > 1

Answer 17

reaction favours products

Question 18

Keq is greater than 10^10

Answer 18

rxn goes to completion

Question 19

Keq = 1

Answer 19

at equilibrium, concentration of reactants = concentration of products

Question 20

Keq < 1

Answer 20

rxn favours reactants

Question 21

Keq less than 10^-10

Answer 21

rxn has not taken place