Topic 13 : Reversible Reactions + Haber Process

Question 1

what are reversible reactions?

Answer 1

• reactions where the products can react to turn back into the original reactants
  _ they have a double arrow to signify this

Question 2

what happens when a reversible reaction takes place in a closed system?

Answer 2

• none of the reactants or products can escape and nothing else can get in the reaction
• so it will always reach dynamic equilibrium

Question 3

what is dynamic equilibrium?

Answer 3

• conc of reactants and products remain constant
• the forwards and backwards reaction happen at same rate
• the overall effect of the reaction is nil

Question 4

how does the position of the equilibrium affect conc of reactants or products?

Answer 4

• if it lies to the right : favours forwards reaction so conc of products is greater
• if it lies to the left vice versa

Question 5

Le Chatelier’s Principle

Answer 5

• if you change the conditions of a reversible reaction at equilibrium
• the system will try to counteract that change and the yield of the reaction
• position of equilibrium will change

Question 6

what 3 factors causes position of equilibrium to change

Answer 6

• temperature
• pressure
• concentration of reactants or products

Question 7

changing temp

Answer 7

• increase temp = equilibrium moves in endothermic direction and this is favoured
• decrease temp = opposite

Question 8

changing pressure

Answer 8

• increasing pressure = favours reaction which produces less moles of gas
• decrease pressure = opposite

Question 9

changing conc

Answer 9

• increase conc of reactant = system tries to decreases it by making more products
• increase conc of product =vice versa

Question 10

Haber Process

Answer 10

• reversible reaction between nitrogen and oxygen that makes ammonia
• n2 + 3h2 -> 2nh3

Question 11

conditions of Haber Process

Answer 11

• nitrogen obtained from air
• hydrogen extracted from hydrocarbons
• temp : 450 - pressure : 200 atmospheres - iron catalyst