Based on the following balanced equation: H2 + O2 à H2O
How many moles of O2 are required to react completely with 2.00 moles of H2

Moles of O₂ are required : 1 mol

Given

2.00 moles of H₂

Required

moles of O₂

Analysis

Balanced equation

Find mol ratio O₂ and H₂

Solution

Balanced equation

2H₂ + O₂ → 2H₂O

From the equation, the mol ratio of H₂ : O₂ = 2 : 1, so mol O₂ :

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 !