Explanation:
According to the law of conservation of mass, mass can neither be created nor it can be destroyed. But it can be simply transformed from one form to another.
Therefore, when
is added to NaCl then the compound formed will have same mass as that of reactants.

Total mass of reactants is (169.87 + 58.44) g/mol = 228.31 g/mol
Total mass of products is (143.32 + 84.99) g/mol = 228.31 g/mol
Thus, we can conclude that mass of the new mixture will stay the same.
Both products will start to cancel the acidity and how strong the base is if they are mixed. If the acid is stronger than the base then it will be an acidic product and visa versa if the base is stronger than the acid.
Actually, we can answer the problem even without the first statement. All we have to do is write the reaction for the production of sulfur trioxide.
2 S + 3 O₂ → 2 SO₃
The stoichiometric calculations is as follows:
7 g S * 1 mol/32.06 g S = 0.218 mol S
Moles O₂ needed = 0.218 mol S * 3 mol O₂/2 mol S = 0.3275 mol O₂
Since the molar mas of O₂ is 32 g/mol,
Mass of O₂ needed = 0.3275 mol O₂ * 32 g/mol = 10.48 g O₂
The factor in determining the average atomic mass of an element is:
B or 2 relative abundance of each isotope because the by looking at how many protons , electrons and neutrons the most isotope is of the element has relative abundance.