Redox

Heating hydrated copper(II) sulfate (CuSO₄·5H₂O) drives off water, changing it from blue to anhydrous white copper(II) sulfate (CuSO₄). This favors the reverse reaction. Cooling and adding water reverses this, returning it to the blue hydrated form.

Anhydrous cobalt(II) chloride (CoCl₂) is blue. Adding water causes it to become hydrated cobalt(II) chloride (CoCl₂·6H₂O), which is pink. The forward reaction (anhydrous to hydrated) is favored.

Increasing the temperature shifts the equilibrium position to favor the endothermic reaction. For an exothermic forward reaction, this means the equilibrium will shift to the left, favoring reactants and reducing product yield.

Increasing the pressure shifts the equilibrium position to favor the side with fewer moles of gas.

A catalyst does NOT affect the position of equilibrium. It only speeds up the rate at which equilibrium is reached, by lowering the activation energy for both forward and reverse reactions equally.

The symbol equation for the Haber process is N₂(g) + 3H₂(g) ⇌ 2NH₃(g). This represents the reversible reaction between nitrogen and hydrogen to produce ammonia.

The hydrogen in the Haber process comes from methane (natural gas). The nitrogen comes directly from the air.

The Haber process typically uses the following conditions: 450°C, 20,000 kPa (200 atm) pressure, and an iron catalyst.

The key reaction is the conversion of sulfur dioxide to sulfur trioxide: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g).

The sulfur dioxide (SO₂) comes from burning sulfur or roasting sulfide ores. The oxygen (O₂) is obtained from the air.