The table lists standard Gibbs free-energy changes for three reactions

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

The table lists standard Gibbs free-energy changes for three reactions. 1) P + Q

\rightarrow

\Delta G^{\circ}=+28\,\text{kJ}

2) R

\rightarrow

S + T

\Delta G^{\circ}=-40\,\text{kJ}

3) 2 S

\rightarrow

\Delta G^{\circ}=+5\,\text{kJ}

Using only these reactions, determine

\Delta G^{\circ}

for the overall reaction Q + S

\rightarrow

T under standard conditions. (a)

+7\,\text{kJ}

(b)

-12\,\text{kJ}

(c)

-7\,\text{kJ}

(d)

-17\,\text{kJ}