Equilibrium Flashcards
1st year equilibrium: mention _____in answer
Effect on yield
1st year equilibrium: 3 important points
- dynamic equilibrium
- homogeneous equilibrium
- equilibrium law
dynamic equilibrium?
( equilibrium bit) Rate of forwards and backwards reactions are equal (dynamic bit) and reactions continue at a molecular level
homogeneous equilibrium?
all particles in the equilibrium system are in the same state
equilibrium law?
at eq., the [products]/ [reactants] = constant
• amounts of r and p don’t change
Kc general?
- The eq. constant
- Kc tells us the relative proportion of reactants and products present at eq.
- [r] and [p] DO NOT CHANGE AT EQ.
- the units for Kc must be worked out for each question
if there are no units?
must write no units,, can’t just leave it blank
for the equilibrium constant?
need the conc at EQUILIBRIUM
Equilibrium constant is constant unless
the temperature is changed.
Kp vc Kc?
Kp for gases
Kc for liquids but Kc can be used for gases too
Mole fraction, x, equation
Mole fraction = moles of the gas/ total n of all gases
all x values add to?
1
partial pressure is?
the contribution a gas makes to the total pressure
partial pressure symbol
p
total pressure symbol
P
Partial pressure equation?
p = xP pp = mole fraction x total pressure
the sum of the partial pressure =?
total pressure
Kp =
pproducts/ preactants
when working out, K ignore?
solids, leave them out of the equation
Effect of changing temp on K?
- ony thing that changes K
- an ⬆ in temp shifts the eq. in the endothermic direction
- a ⬇ in temp shifts the equilibrium in the exothermic direction
- value of K has to change w temp
effect of increasing temp on K?
- of the forwards reaction is endothermic, and the temp is ⬆
- the equilibrium yield of the products would ⬆
- eq. yield of the reactants would decrease
- so K would decrease
the opposite is true for exothermic reactions when temp increases
when explaining the impact of changing conc/ pressure on K include these in the answer
- Kc/Kp expression
- theoretically what would happen
- what actually happens - equilibrium shift
- impact on Kc - none
impact of adding a catalyst on the value of K?
- does not change
- bc does not impact position of eq.
- the forwards and backwards reactions are sped up equally so eq is established faster
Kp and Kc are?
temp dependent constants