When we write a chemical equilibrium we call the species on the left of the reaction the "reactants" and the species on the right of the reaction the "products". In the example that we have been using (N2 + 3H2 2NH3) N2, and H2 would be considered the reactants and NH3 would be considered the product.

However, in reality at equilibrium we have a mixture of all of the species. When we write
N2 + 3H2 2NH3 Kc = 0.25, this just tells us that we can start with N2 and H2 and end up with an equilibrium mixture of N2, H2, and NH3. It also tells us that we can start with NH3 and end up with and equilibrium mixture of N2, H2, and NH3.

Let's try starting with just NH3 and allowing an equilibrium to form. Place 5 moles of NH3 into the reaction vessel. However, before you press "equilibrate", answer the following questions:

Look at the contents of the reaction chamber initially and at equilibrium. If you did not understand any of the last questions perhaps looking at the initial and equilibrium concentrations will help you understand them. If you have questions you may want to see your instructor.

Last question!

Why would it be very difficult to have a container of pure NH3 gas?

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