Balancing of chemical equation is essential because of the law of conservation of mass, which states that the mass of a system can not be created or removed.
The second equation is balanced
This is because the number of elements of each atom in the product side equal the number of elements of each atom on the reactant side.
The first equation is not balanced

This is because there is 1 molecule of
on reactant side as compared to 3 molecules of 
To balance the equation we add a coefficient of 3 on sulphuric acid (
) and a coefficient of 3 on hydrogen (
)

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:
6 g S * 1 mol/32.06 g S = 0.187 mol S
Moles O₂ needed = 0.187 mol S * 3 mol O₂/2 mol S = 0.2805 mol O₂
Since the molar mas of O₂ is 32 g/mol,
Mass of O₂ needed = 0.2805 mol O₂ * 32 g/mol = 8.976 g O₂
Answer:
This reaction is characteristic to metal carbonates, which decompose when heated to form the oxide of the metal and carbon dioxide gas.
Explanation:
Just did it...
Description:
<span>"0.0400 mol of H2O2 decomposed into 0.0400 mol of H2O and 0.0200 mol of O2."
This means that a certain amount of H2O2 (0.0400 mol) decomposed or was broken down into two components, 0.04 mol of H2O and 0.02 mol of O2. To examine the system, we need a balanced equation:
H2O2 ---> H2O + 0.5O2
The final concentrations of the system indicates that the system is in equilibrium. </span>