# Chemistry

Enthalpy questions?
Given this enthalpy change
MgCl₂(s)---->Mg²⁺(g) +2Cl⁻(g)
ΔH∅ =+2490KJ/mol

Mg2+(g)----> Mg²⁻ (aq)
ΔH∅ =-1920KJ/mol

Cl⁻(g)---->Cl⁻(aq)
ΔH∅ =-360KJ/mol
What is the Enthalpy change in KJ/mol for following process

MgCl₂(s)---->MgCl₂(aq)

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1. 1. I believe your equation 2 is a typo and you meant Mg^2+ and not Mg^2-.
2. I believe you need another equation that reads
Mg^2+(aq) + 2Cl^-(aq) ==> MgCl2(aq) dH = ? Call that equation 4.
Then add your equation 1, 2, 2*3 and the missing equation 4

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2. Given this enthalpy change
MgCl₂(s)---->Mg²⁺(g) +2Cl⁻(g)
ΔH∅ =+2490KJ/mol

Mg^2+(aq) + 2Cl^-(aq) ==> MgCl2(aq) Hº(reaction) = -462 kJ/mol

Mg2+(g)----> Mg²⁻ (aq)
ΔH∅ =-1920KJ/mol

Cl⁻(g)---->Cl⁻(aq)
ΔH∅ =-360KJ/mol
What is the Enthalpy change in KJ/mol for following process

MgCl₂(s)---->MgCl₂(aq)

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3. What part of "there is no Mg^2- do you not understand"?
Also, I don't see the other equation you need.
The only new information is you posted the answer and just reposted the original question along with the incorrect equation with the Mg^2-.

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