CHEMISTRY COMMUNITY

For this problem, it asks for the equilibrium concentration of H2, given the equilibrium constant and that there is a "gas-phase equilibrium mixture of H2, I2, and HI at 500. K." How do we know if H2/I2 are the products or the reactants?

The question asks you to refer to the chart from Table 11.2

The table gives you the reaction and the K value needed to find the equilibrium concentration of H2.

With the given equation, I came up with:
794=[2.21x10^-3]^2/[X][1.46x10^-3]
can someone check my equation for accuracy? and then tell me the steps after to get the H2 concentration because I got 4.21x10^-6 when the answer is 2.1x10^-5?

In regards to my above post, could my incorrect answer be due to not considering the 1:2 ratio between H2 and HI? and possibly a sig fig error?

The K value you used was probably incorrect. When you look at table 5G.2, there are multiple K and Kc values for each equation. The second column (the first one with the numbers) is the temperature. The K you used, 794, is for the reaction taking place at 298 K. In the problem, it is 500 K and the K value for that is 160.