P- Equilibria (P2) =) Flashcards
Explain how the addition of a catalyst changes the activation energy. (2)
- alternative route
- w/ a ↓ Ea (∴ ↑ molecules can react)
Explain the meaning of the term dynamic equilibrium. (2)
- rate of forward reaction = rate of reverse reaction
- conc. of reactants + products remain constant
Suggest two reasons why the operation of this process at a pressure much higher than 5 MPa would be very expensive. (2)
- energy required to provide high pressure
- strong pressure vessels needed- withstand high pressure
CH4 (g) + 2H2O (g) ⇌ CO2 (g) + 4H2 (g)
The mixture was placed in a flask of volume greater than 5.0dm3 and allowed to reach equilibrium at the same temperature.
State and explain the effect on the amount of hydrogen. (3)
↑
- ↓ pressure
- eq. shifts to RHS w/ ↑ moles
State the Le Chatelier’s principle. (1)
Position of equilibrium moves to OPPOSE any change.
made it up from memory- better check.
Explain how the use of a catalyst affect the cost of a reaction. (2)
- allows a lower temp to be used
- ↓ cost
State and explain the effect of using a catalyst on the yield of methanol in this equilibrium. (2)
- x effect
- ↑ rate of forward + reverse reactions equally
2A + B ⇌ 3C + D
Justify the statement that adding more water to the equilibrium mixture will lower the amount of A in the mixture. (3)
- conc (of all) ↓
- eq. shifts to the sides w/ ↑ moles
- to oppose ↓ in conc
x dilution
Define the term catalyst. (2)
- speeds up a chemical reaction
- remains unchanged
At high temperatures, nitrogen is oxidised by oxygen to form nitrogen monoxide in a reversible reaction as shown in the equation below.
N2(g) + O2(g) ⇌ 2NO(g)
State and explain the effect of an increase in pressure on the yield of nitrogen monoxide in the above equilibrium. (3)
- no effect
- same no. of gaseous moles on either side
- both sides affected equally
