ChemistryCode 5070
Reversible reactions and equilibrium
What this topic asks you to be able to do
- State that certain chemical reactions are reversible, and that the ⇌ symbol is used to show this
- Describe how a reversible reaction's direction can be reversed by varying conditions, in these cases: (a) applying heat to hydrated compounds (b) introducing water to anhydrous compounds, including copper(II) sulfate and cobalt(II) chloride
- State that a reversible reaction taking place in a closed system has reached equilibrium once: (a) the forward and reverse reactions proceed at the same rate (b) reactant and product concentrations are no longer changing
- Predict and explain, using the information supplied, how the position of equilibrium of a reversible reaction responds to: (a) a change in temperature (b) a change in pressure (c) a change in concentration (d) the use of a catalyst
- State the symbol equation, for ammonia manufacture by the Haber process, N2(g) + 3H2(g) ⇌ 2NH3(g)
- Name the origins of the hydrogen gas (from methane) and the nitrogen gas (from air) used in the Haber process
- Give the usual conditions of the Haber process: 450°C, 20000kPa/200 atm, and an iron catalyst
- Give the symbol equation for turning sulfur dioxide into sulfur trioxide in the Contact process: 2SO2(g) + O2(g) ⇌ 2SO3(g)
- State where the Contact process obtains its sulfur dioxide (by burning sulfur, or by roasting sulfide ores) and its oxygen (from air)
- State the usual conditions the Contact process uses to turn sulfur dioxide into sulfur trioxide: 450°C, 200kPa/2 atm and a vanadium(V) oxide catalyst
- Account for, using reaction rate and equilibrium position, why the usual conditions named are chosen in both the Haber process and the Contact process, including safety factors and economic issues