How formula unit mass is different from molecular mass?

An element X forms X₂(CO₃)₃ type compound. What is the formula of its phosphate and chloride?

Write the formula of the following compounds.

(i) Magnesium sulphate

(ii) Sodium bromide

(iii) Calcium chloride

(iv) Potassium nitrate

(v) Sodium phosphate

Which one is a larger quantity molar mass or molecular mass? Explain.

Calculate the molar mass of the following compounds:

(i) MgO (ii) Na₂CO₃

(iii) H₃PO₄ (iv) Ca(OH)₂

(v) Al₂(SO₄)₃