How many moles of hydrogen, h2, are needed to react with 4.0 moles of nitrogen, n2

6 moles because you start with a balanced equation and with the balanced equation it means that regardless of how many miles of nitrogen gas you have, the reaction will always consume twice as many miles if hydrogen gas.

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.