Question

Even though so much energy is required to form a metal cation with a 2+ charge, the alkaline earth metals form halides with general formula MX₂, rather than MX.
(a) Use the following data to calculate ΔH° f MgCl
Mg(s) → Mg(g) ΔH° = 148 kJ
Cl₂(g) → 2Cl(g) ΔH° = 243 kJ
Mg(g) → Mg⁺(g) + e⁻ ΔH° = 738 kJ
Cl(g) + e⁻ → Cl⁻ (g) ΔH° = -349 kJ
ΔH° lattice of MgCl = 783.5 kJ/mol

Answer 1

The ∆Hrxn of the reaction is -394.5kJ/mol.

What is alkaline earth metal?

The alkaline earth metals are those elements which correspond to group 2 of the modern periodic table.

All elements of this group forms a cation of +2 charge.

The other elements of this group are:

Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium.

What is Halogen?

The Halogen elements are present in group 17 of the modern periodic table.

All elements of this groups forms anions of -1 charge.

The elements of this group are:

Fluorine, Chlorine, bromine, iodine, and astatine.

∆Hrxn = ∆H(bond broken) - ∆H(bond formed)

We have following data of bond energy in kJ/mol:

Mg—Mg = 738

Cl—Cl = -349

Mg—Cl = 783.5

Since, one mole of Mg react with one mole of Cl atom to form one mole of MgCl

∆Hrxn = 738-349-783.5

∆Hrxn = -394.5kJ/mol.

Thus, we concluded that the ∆Hrxn of the reaction is -394.5kJ/mol.

learn more about bond energy:

brainly.com/question/13526463

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