Equilibria ( AS ) Flashcards
Define the term dynamic equilibrium
The rate of forward reaction is equal to the rate of backward reaction
(Hence, the concentration of reactants and products don’t change)
Give an essential condition for an equilibrium mixture
Equilibrium occurs in a closed system(where reactants and products can not escape)
State Le Chateliers principle
If a system at equilibrium is disturbed, the system will shift equilibrium in the direction that opposes the disturbance.
In this equation:
CH4(g)+H20(g)⇌CO(g) +3H2(g)
ΔH°=+210kJmol-1
What effect would increasing the temperature have on the position of equilibrium?
The position of the equilibrium shifts to the right
(This is because the forward reaction is endothermic. Yield of hydrogen increases)
What would be the effect of increasing pressure on the position of equilibrium(Haber process)
The equilibrium position shifts to the right
This is because the equilibrium moves to the side with fewer gas molecules
What effect does a catalyst have on the position of equilibrium?
No effect
A catalyst speeds up the rate of forward and backwards reaction equally
Why are the temperature and pressure used in the Haber process considered to be a compromise?
High pressure/ low temperatures move equilibrium to the right. Both have compromise value as very high pressure is expensive, and low temperatures slow the rate of reaction
What is the equation for heating of hydrated copper sulfate?
CuSO4.5H2O⇌CuSO4+5H2O
What colour is anhydrous copper sulfate?
White
What conditions affect the value of Kc?
Temperature
For the reaction below, deduce an expression for Kc.
2[A]+3[B]+[C]⇌[D]+4[E]
Kc= [D][E]⁴/[A]²[B]³[C]
Deduce the units for the value of Kc
Mol-1dm³
What does Kc being greater or less than 1 suggest for the position of equal?
Greater than 1= over to the right
Less than 1= over to the left
What effect does decreasing the temperature in an endothermic reaction have on Kc?
Kc decreases
What effect does increasing the temperature in an endothermic reaction have on Kc?
Kc increases
