In an industrial chemical plant, the synthesis of ammonia is represented by the following chemical equation:

Identify the specific feature in this equation that shows the reaction is reversible.

The forward reaction to synthesize ammonia is exothermic. State the type of energy change associated with the reverse reaction.

In industrial reactors, a finely divided iron catalyst is used. Select two reasons from the list below why a catalyst is employed in this process:

• To raise the operating pressure
• To minimize overall thermal energy demands
• To consume less nitrogen feedstock
• To lower manufacturing operating costs
• To shift the equilibrium position to the right

Table 1 shows data about the nutrient content of four different fertilisers, A, B, C, and D.

Table 1

• Fertiliser A: 34.0% nitrogen, 0.0% phosphorus, 0.0% potassium
• Fertiliser B: 21.0% nitrogen, 0.0% phosphorus, 0.0% potassium
• Fertiliser C: 15.0% nitrogen, 30.0% phosphorus, 0.0% potassium
• Fertiliser D: 0.0% nitrogen, 0.0% phosphorus, 52.0% potassium

Which combination of two fertilisers provides all three of the essential elements needed for an NPK fertiliser?

• A and C
• B and D
• C and D
• A and B

Which fertiliser from Table 1 is not manufactured using ammonia as a raw material?

• A
• B
• C
• D