Chemical equilibrium is a condition where the rate of product made is same as the rate of reactant made. Since the reaction to the left is same as the reaction to the right, so the amount of reactant and product will not be changed (doesn't mean that the amount is same, it just won't increase or decrease).
It's called equilibrium since there will be no change in their amount.
The relative atomic mass (Ar) : 137 and the element : Ba
<h3>Further explanation
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The naming of chemical compounds is giving a special name to a compound that aims to facilitate the classification of compounds and facilitate the identification of a compound. The rules for naming chemical compounds have been determined by the IUPAC (International Union of Pure and Applied Chemistry)
This nomenclature includes the naming of ion compounds, covalent compounds, and polyatomic
The molar mass of a compound is given by the sum of the relative atomic mass of Ar
M AxBy = (x.Ar A + y. Ar B)
Group 2 metals have a +2 charge : M²⁺
So the compound of metal carbonate : MCO₃
Ar C = 12, O = 16
M MCO₃ = (1.Ar M + 1. Ar C+ 3. Ar O)

The element with relative atomic masses 137 is Ba
So the compound : BaCO₃
I think we need more information
(10.0 g Al2(SO3)3) / (294.1544 g Al2(SO3)3/mol) = 0.033996 mol Al2(SO3)3 (10.0 g NaOH) / (39.99715 g NaOH/mol) = 0.25002 mol NaOH
0.033996 mole of Al2(SO3)3 would react completely with 0.033996 x (6/1) = 0.203976 mole of NaOH, but there is more NaOH present than that, so NaOH is in excess and Al2(SO3)3 is the limiting reactant.
Answer:
2H2 + O2 -----> 2H2O
Not sure about the second question though.