If you have 1.90 moles of H_2 How many grams of NH_3 can be produced?
Start with the balanced reaction, you did not specify it. There are a number of reactions with H2 to make ammonia. Lets assume the Haber process.
3H2 + N2 >> 2NH3
so it appears you get 2/3 the moles H2 when making NH3
2/3 * 1.9= you do it.
Now convert that to grams of NH3