Reversible Reactions ↔️ Flashcards
What is a reversible reaction?
A reaction in which the products can react and form the original reactants.
How can the direction of a reversible reaction be altered?
Changing the reaction conditions.
E.g. temperature, pressure, concentration.
What is meant by the term dynamic equilibrium?
Dynamic equilibrium is when the rate of the forward reaction equals the rate of the backwards reaction. This means the concentration of reactants and products are constant even though compounds are continually reacting.
What is a closed system?
A system where nothing is added or removed. All reactants and products remain in the reaction vessel.
Why is equilibrium only reached if the reaction takes place in a closed system?
The closed system prevents any reactants and products escaping so that they are able to react continuously.
What is the Haber process?
An industrial process used to produce ammonia (for making fertilisers).
Write the chemical equation for the reversible reaction between nitrogen and hydrogen, forming ammonia.
N2 + 3H2 ⇌ 2NH3
Where are the sources of nitrogen and hydrogen for the Haber process?
Nitrogen: Extracted from the air.
Hydrogen: Obtained from natural gas.
What conditions are used for the Haber process?
- 450°C temperature
- 200 atm pressure
- Iron catalyst
Explain the effect of increasing the temperature of a reversible reaction if the forward reaction is endothermic.
The forward reaction is endothermic so increasing the temperature favours the forward reaction. The equilibrium will shift towards the forward reaction and the yield of the products will increase.
Explain the effect of increasing the pressure of a reversible gaseous reaction.
An increase in pressure will favour the reaction that produces the LEAST number of molecules. The equilibrium position will shift towards the side that produces the FEWEST gaseous molecules.
The equation for the Haber process is
N2 + 3H2 ⇌ 2NH3
Explain the effect of increasing the pressure on the yield of ammonia.
Increasing the pressure will shift the equilibrium to the right as there are FEWER molecules of gas. The yield of ammonia will increase.
The concentration of the reactants are increased during a reversible reaction. What effect will thus have on the equilibrium position?
The equilibrium will shift to the right so the yield will increase. This will reduce the effect of the increased concentration of the reactants.
If there are equal gaseous molecules of the reactant and product in a reversible reaction, what effect will changing the pressure have on the equilibrium position?
No effect
