When 1.029 mol of gaseous HI is sealed in a 1.00-L flask at 225°C, it decomposes until the equilibrium amount of I2 present is 0.187 mol:
2HI(g) ⇔ H2(g) + I2(g)
Use these data to calculate Keq for this reaction at 225°C.

Question

When 1.029 mol of gaseous HI is sealed in a 1.00-L flask at 225°C, it decomposes until the equilibrium amount of I2 present is 0.187 mol: 
2HI(g) ⇔ H2(g) + I2(g)
Use these data to calculate Keq for this reaction at 225°C.

jfraser · Answer

you know how much HI you start with, and you know how much I2 you finish with. How much H2 must you also finish with?

anonymous · Answer

I dont know..

jfraser · Answer

look at the reaction. You start with all HI and no H2 and no I2. By the time equilibrium is established, you've got 0.187mol of I2. How much H2 must also be made?