N2(g) + 3 H2(g) 2 NH (g) 12 How many moles of hydrogen are consumed to produce 100 g of ammonia?
A 17.8 mol H2
B. 17.6 mol HE
C 8.80 mol H2
D3 91 mol H2

This is a stoichometric ratio

Explanation:The equation is already balanced, so all you have to do is.

1. Count the molar mass of Ammonia N nitrogen atom has an atomic mass of 14 so add 14+ 3 hydrogens which each have a mass of 1 that gives you 17 grams per mole of ammonia on the right side, so they want to know how much hydrogen is needed to make 100 grams of ammonia, so what you have to do is divide 100/17=2.94 that is your ratio so you now know there is 2.94 times everything in the equation so at first you had 3 moles of hydrogen now you have 3*2.94 moles of hydrogen. You also have 2.94 moles of N2 gas. It's just a ratio if you plug in 200 instead you have to multiply everything by 200/17=11.76 ratio.

1st step count molar mass of product.

2nd plug number they gave you and divide it by molar mass ratio then multiply everything in equation by that ratio.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !