The equation for a reaction that occurs in the gas phase is: N2O4(g)⇌2NO2(g)ΔH=+57 kJ/mol\text{N}_2\text{O}_4(g) \rightleftharpoons 2\text{NO}_2(g) \quad \Delta H = +57 \text{ kJ/mol}N2O4(g)⇌2NO2(g)ΔH=+57 kJ/mol.
(i) State the meanings of the symbols ⇌\rightleftharpoons⇌ and ΔH\Delta HΔH. (ii) What does the positive sign of ΔH\Delta HΔH indicate about the reaction?
Describe how to complete an energy level diagram for this reaction, specifying the relative vertical positions of the lines for the reactants and the products.
Typical conditions used for this reaction are a temperature of 100∘C100^\circ\text{C}100∘C and a pressure of 5 atm5\text{ atm}5 atm. Deduce the effects of changing the conditions as shown below (choose from the words increased, decreased or unchanged): (1) Effect of an increase in temperature on the rate of reaction and on the yield of products; (2) Effect of the addition of a catalyst on the rate of reaction and on the yield of products.
A manufacturer considers using a pressure of 10 atm10\text{ atm}10 atm instead of 5 atm5\text{ atm}5 atm. (i) Predict and explain the effect on the rate of reaction of changing the pressure to 10 atm10\text{ atm}10 atm. (ii) Predict and explain the effect on the position of equilibrium of changing the pressure to 10 atm10\text{ atm}10 atm.
Balance the equation representing the reduction of nitrogen dioxide by carbon monoxide in a catalytic converter: …NO2+…CO→…N2+…CO2\dots\text{NO}_2 + \dots\text{CO} \rightarrow \dots\text{N}_2 + \dots\text{CO}_2…NO2+…CO→…N2+…CO2.
28 exam-style questions on Edexcel IGCSE Chemistry Reversible reactions and equilibria. Each one has a worked solution and a mark scheme showing where the marks go.