Question

Given, \[2{{H}_{2}}+{{O}_{2}}\to 2{{H}_{2}}O\]. In the above equation, for 4g of hydrogen ……… grams \[{{O}_{2}}\]is required.

Answer 1

Hint: Molecular mass is generally represented by m and it is the mass of a given molecule. Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. Isotopes are those compounds which have the same number of protons but different numbers of neutrons.

Complete answer:
The given reaction is the process of making water molecules by combining \[{{H}_{2}}\]and \[{{O}_{2}}\]. As we all know that water is a lifeline for us there is no life without water so the reaction has much more importance. Although reactions are of several types out of which we discuss balanced and unbalanced reactions. Balanced reactions are those in which the number of molecules present in the reactant is equal to the number of molecules present in product while unbalanced have different molecules in case of reactant and product.
The reaction given in the question is balanced in nature i.e. there are four hydrogen molecules and two oxygen molecules in the reactant and the same number of molecules is present in the product.
\[2{{H}_{2}}+{{O}_{2}}\to 2{{H}_{2}}O\]
Molecular mass of \[{{H}_{2}}\]= \[2gmo{{l}^{-1}}\]
Molecular mass of \[{{O}_{2}}\]= \[32gmo{{l}^{-1}}\]
Hence the equation given above is balanced in nature,
So we can say that $2\times 2=4g$ of hydrogen requires 32g of oxygen to react completely.

Hence the answer is 32g \[{{O}_{2}}\] is required for 4g of hydrogen.

Note:
The molecular mass of small and medium size molecules can be measured with the help of mass spectrometry and also used to determine the composition of elements in the molecule. The molecular masses of macromolecules like proteins can also be determined by mass spectrometry.