how many grams of hydrogen are required to react completely with 400g nitrogen to form ammonia? Pls help

N2+3H2-->2NH3

first we find the number of nitrogen moles

the molar mass for N2 is 14+14=28g/mole

to find the number of moles we divide the mass by the molar mass

n=400/28=14.28 moles

for 1 mole of N2 we use 3 moles of H2, therefore for 14.28 moles of N2 we use 14.28*3=42.84 moles ofH2

to find the mass of H2 we multiply the number of moles by the molar mass

the molar mass of H2 is 2g/mole

2*42.84=85.68g of H2

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements