Consider these hypothetical chemicalreactions:
{\rm a \rightleftharpoons b}, \quad\delta g = 13.2 kj/mol
{\rm b \rightleftharpoons c}, \quad\delta g = -28.9 kj/mol
{\rm c \rightleftharpoons d},\quad \delta g = 5.80 kj/mol
what is the free energy, delta g, for the overall reaction, \rm a \rightleftharpoons d ?
express your answer numerically inkilojoules per mole.