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What is the value for ∆Soreaction for the following reaction, given the standard entropy values? 2 Al (s) + 3Cl2(g) 2AlCl3(s)


-503 J/K


+503 J/K


-140 J/K


+140 J/K

What is the value for Soreaction for the following reaction, given the standard entropy values? 2 Al (s) + 3Cl2(g) 2AlCl3(s) -503 J/K +503 J/K -140 J/K +140 J/K class=

Verified Answer :

2Al(s) + 3Cl₂ → 2AlCl₃

Forming the equation:
2(28) + 3(223) = ΔH + 2(111)
ΔH = 503 kJ

Writing this outside of the reaction equation:
ΔH = -503 kJ

Answer: -503 J/K

Explanation:

The balanced chemical reaction is,

\(2Al(s)+3Cl_2(g)\rightarrow 2AlCl_3\)

The expression for enthalpy change is,

\(\Delta S=\sum [n\times S^0(product)]-\sum [n\times \Delta S^0(reactant)]\)

\(\Delta S=[(n_{AlCl_3}\times S_{AlCl_3})]-[(n_{Cl_2}\times S_{Cl_2})+[(n_{Al}\times S_{Al})]\)

where,

n = number of moles

Now put all the given values in this expression, we get

\(\Delta S=[(2\times 111)]-[(3\times 223)+(2\times 28)]\)

\(\Delta S=-503J/K\)

Therefore, the entropy change for this reaction is, -503J/K