CHEMISTRY COMMUNITY

From Lavelle's Week 10 Review slides that he posted, On the first slide, how do you get the change in molar concentration? I am confused with how 0.075 and 0.225 were calculated.

.0150 mol NH3 was formed, which means that half that amount of N2(.075) decreased. This occurs because the stoichiometric coefficient of NH3 is 2 and the coefficient for N2 is 1. The same goes for the H2 but it decreases by 1/3 of the amount of NH3 formed.

you have to use the ratios as well as the actual numbers and do stoichiometry

We know that the equilibrium concentration of NH3 is 0.150 M, so using stoichiometric ratios and an ICE chart we can determine that the concentrations of N2 and H2 decrease by 0.075 M and 0.225 M, respectively.

Using the stoichiometric ratios and creating an ice table you should be able to calculate the molar concentrations

By knowing the change in one of the reactants/products over the reaction, we can use the stoichiometric ratio to calculate the change for the others.