1.10 Equilibrium constant Kp Flashcards
2 SO2(g) + O2(g) ⇌ 2 SO3(g)
State and explain the effect, if any, of a decrease in overall pressure on the
equilibrium yield of SO3
Decreases
equilibrium shifts to the side with fewer moles hence shifts to the left to oppose the decrease in pressure
Stays the same
CO(g) + 2 H2(g) ⇌ CH3OH(g)
Some more carbon monoxide is added to the mixture in part (b). The new mixture is allowed to reach equilibrium at temperature T.
State the effect, if any, on the partial pressure of methanol and on the
value of Kp
effect on partial pressure : increases
effect on Kp : no effect
State the effect, if any, of the addition of a catalyst on the value of Kp for
an equilibrium.
No effect
increases rate of forward and backward reaction by the same amount as a catalyst does not affect position of equilibrium
2 SO3(g) ⇌ 2 SO2(g) + O2(g)
For this reaction at 500 K the equilibrium constant, Kp = 3.94 x 10^4 Pa
calculate the value of Kp, at 500 K, for the
equilibrium represented by this equation.
SO3(g) ⇌ SO2(g) + 1/2 O2(g)
Deduce the units of Kp
square root of original kp = 198.5
kPa^1/2
Nitrogen reacts with hydrogen in this exothermic reaction
N2(g) + 3 H2(g) ⇌ 2 NH3(g)
Which change increases the equilibrium yield of ammonia but has no effect on the value of the equilibrium constant Kp?
A Add a catalyst
B Increase the partial pressure of
nitrogen
C Decrease the temperature
D Decrease the total pressure
B
The enthalpy change for the reaction is –92 kJ mol1
State the effect, if any, of an increase in temperature on the value of Kp for this reaction.
Justify your answer.
Effect on Kp
Decreases
equilibrium shifts to the left
to oppose increase in temperature
Which statement about Kp is correct for this reaction in the gas phase?
W + X + Y2 ⇌ WXY + Y
ΔH = −46 kJ mol−1
A The value of Kp is independent of pressure.
B
The value of Kp increases as pressure
increases.
C
The value of Kp increases as temperature
increases.
D
The value of Kp is independent of
temperature
A
Mean bond enthalpy of H-H bond is 480 kJ mol^-1 and A data book value for the H–H bond enthalpy is 436 kJ mol−1.
Suggest one reason why this value is different from mean bond enthalpy
mean bond enthalpies are not the same as actual bond enthalpies in water
A Catalysts converts emissions into methanol. Suggest one environmental advantage of manufacturing methanol fuel by
this reaction
The carbon dioxide produced on burning methanol is used up in
this reaction
CO2(g) + 3H2(g) -> CH3OH(g) + H2O(g)
Suggest why the catalyst used in this process may become less efficient if
the carbon dioxide and hydrogen contain impurities.
impurities of sulfur compounds block the active sites
