Question

What is the enthalpy of formation of tetrachloroethane from ethene and chlorine

Answer 1

Enthalpy of formation$=\Delta Hf$

The equation for the reaction is

C₂H_4(g) +2Cl_2(g)$\to$ C₂H₂Cl_4(l)

$\Delta Hf^0=\lbrace m\Delta Hf \lbrack products\rbrack\rbrace-\lbrace n\Delta Hf\lbrack reactants \rbrack\rbrace$

$\Delta Hf$ of C₂H₄ $=52.4kJ/mol$

$\Delta Hf$ of Cl₂$=0kJ/mol$

According to Gundry and Head , 1978, $\Delta Hf$ of tetrachloroethane is $-193.5kJ/mol$

therefore,

$\Delta Hf^0=\lbrace-193.5kJ/mol\rbrace-\lbrace\lbrack52.4+(2*0)\rbrack kJ/mol\rbrace$

$\Delta Hf^0=-245.9kJ/mol$