#### Gas-Phase Chemical Equilibrium: Interactive Simulations

These simulations were prepared using Mathematica. Download the free Wolfram player, and then download the simulation CDF file (link given below or click on figure to download). Try to predict the behavior when a parameter changes before using a slider to change that parameter. For these simulations, screencasts are provided to explain how to use them.

##### Simulation: Chemical Equilibrium in the Haber Process

The number of moles at equilibrium is calculated for the Haber process, which is the reversible, exothermic reaction that synthesizes ammonia (NH3) from hydrogen (H2) and nitrogen (N2). The reaction is typically carried out at around 200 bar and 675–725 K. You can vary the pressure and temperature in this Demonstration. Gases are assumed to behave ideally, although realistically at the high pressures used in this reaction, there is significant deviation from ideal behavior. At equilibrium, you can add additional nitrogen, hydrogen, and/or ammonia at constant pressure, and the effect on the equilibrium is observed.

Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.

1. As temperature increases, does the number of moles of NH3 increase or decrease?
2. As pressure increases, does the number of moles of NH3 increase or decrease?
3. Is it possible at low H2 concentrations to add N2 to the system and observe the reaction shifts to the left (i.e., less NH3 is present at equilibrium)?