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

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.

the answer is c.the valence of the atoms combine .