Be sure to answer all parts. identify the main group to which x belongs in each ionic compound formula: (a) xf2; (b) mgx; (c) x2so4 xf2 mgx x2so4

(a) Group IIA.

(b) Group VIA.

(c) Group IA.

Explanation:

Hello,

To solve this problem, one remembers that the subscripts are related with both the cation's and anion's oxidation states exchanging which are also related with the group they belong, thus:

(a) For since the fluoride anion has 2 as the subscript and -1 as its charge, X should belong to group IIA because X has 1 as its subscript.

(b) For since the magnesium cation has 1 as the subscript and it belongs to group IIA, it means that it has +2 and the anion has -2 as the charges, thus, X should belong to group VIA for the nonmetals that have such oxidation state.

(c) For since the sulfate anion has 1 as the subscript, and X has two, X should belong to group IA.

Best regards.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%