How are given mass, molar mass and number of moles related to each other?

In the chemical reaction given below, find the amount of barium sulphate formed. Also write the law involved

Name any two monovalent cations, divalent cations and trivalent cations. Also name any one compound each one of them make.

The symbols of some of the ions are given below

Na⁺, Mg²⁺, H⁺, Cl^–, S^2–

Using this information, find out the formulae of

(i) sodium carbonate

(ii) magnesium chloride

(iii) hydrogen sulphide

Write the chemical formulae of Nitrates (NO₃^–) of Na⁺, K⁺, Al³⁺, Mg²⁺, Ca²⁺, Zn²⁺.