Reversible Reactions Flashcards
When can a reaction reach equilibrium?
In a closed system (a container where no reacting substances can enter or leave)
At equilibrium what is the rate of the forward reaction equal to?
The backward reaction
What happens to the concentration of a substance at equilibrium?
It stays constant
Do the forward and backward reactions stop at equilibrium?
No, they keep going
What is the haber process?
A reversible reaction between nitrogen and hydrogen to form ammonia
What is the reaction to form ammonia?
N2 (g) + 3H2 (g) → 2NH3 (g)
Where is nitrogen extracted from?
From the air
How is hydrogen obtained?
From the natural gas
What does increasing the temperature of an equilibrium reaction do?
Equilibrium position moves in the direction of the endothermic reaction
What does increasing the pressure of an equilibrium reaction do?
Equilibrium position moves in the direction of the fewest molecules of gas
What does increasing the concentration of a reacting substance in an equilibrium reaction do?
Equilibrium position moves in the direction away from the reacting substance
What does adding a catalyst to an equilibrium reaction do?
The equilibrium position doesn’t move
What does changing these conditions of an equilibrium reaction do to the rate of reaching equilibrium?
They all increase the rate of reaching equilibrium (increasing pressure only increases if reacting gases are present)
What are the temperature and pressure conditions of the Haber process?
200 atmospheres and 450 degrees
Why is equilibrium not usually reached in industrial processes?
It would take too long
What are fertilisers?
Soluble substances added to the soil to promote the growth of plants
What are NPK fertilisers?
Fertilisers containing nitrogen, phosphorus, potassium (the main elements that help plants to grow well)
Why are ammonium salts useful as fertilisers?
They are a soluble source of nitrogen
How do hydrogen-oxygen fuel cells work?
Hydrogen and oxygen used to produce a voltage
What are the advantages of chemical cells?
- Cheap
- Suitable for portable appliances
What are the disadvantages of chemical cells?
- Can contain harmful substances
- Do not produce a voltage when one of the reactants is used up
What are the advantages of hydrogen-oxygen fuel cells?
- Produce voltage as long as the fuel and air are supplied
- Produce water vapour as the only waste product
What are the disadvantages of hydrogen-oxygen fuel cells?
- Expensive
- Not suitable for portable appliances
