## Chemistry and Chemical Reactivity (9th Edition)

$-2253.9\ kJ/mol$
$\begin{matrix} Reaction&\Delta H(kJ/mol)&\times\\ \hline Ca(s)\rightarrow Ca(g)&+178.2 &1\\ Ca(g)\rightarrow Ca^+(g)+e^-&+589.83&1\\ Ca^+(g)\rightarrow Ca^{2+}(g)+e^-&+1145.45&1\\ 1/2Cl_2(g)\rightarrow Cl(g)&+121.3 &2\\ Cl(g)+e^-\rightarrow Cl^-(g)& -349 &2\\ Ca^{2+}(g)+2\ Cl^-(g)\rightarrow CaCl_2(s)&x&1\\ \hline Ca(s)+Cl_2(g)\rightarrow CaCl_2(s)&-795.8& \end{matrix}$ Solving for x we get: $-2253.9\ kJ/mol$