CO(g) + H2O(g)-->CO2 + H2 (g) reaction occurs in a 2.0 Ll reactor at 800 degrees celsius. The reaction conditions are such that a complete conversion of reactants into products results. The reactor is charged initially with 5.0 atm of CO and 8.0 atm of water vapor. Calculate the final pressure of hydrogen in the reactor.

(The reaction is balanced already and I know that final pressure can be found by Pf = (initial pressure)(initial volume)/final volume but this has already be hinted at being a limited reactant question of which I'm awful at. So I would assume that I would need to find the mass of H2 (water vapor) and CO but not sure about the mass used in this question in order to divide it by molar mass. Any suggestions or tips?)

1 answer

Since these are 1:1:1:1 you can take a short cut and see that CO is the limiting reagent. So 5 atm CO reacts with 5 atm H2O to form 5 atm CO2 and 5 atm H2 with 3 atm H2O left over. The final P is 16 atm. Your prof may not like this so you can do it conventionally this way.

Calculate mols CO and mols H2O using PV = nRT. All of the information is there to do so. I obtained about 0.11 mols CO and about 0.18 mols H2O but these are estimates and you need to do them more accurately. That will produce about 0.11 mols CO2 and 0.11 mols H2 leaving zero mols CO and about 0.05 mols H2O. Finally, convert mols to pressure and add the total pressure and you will get 16 atm.