Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to $3$ significant figures in $\mathrm{kJ} {\mathrm{mol}}^{-1}$, and in each case state whether or not the reaction is spontaneous under standard conditions.

Given:

$$\begin{gathered} 2\mathrm{Na}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{Na}}_2{\mathrm{O}}_2\left(\mathrm{s}\right); ∆{\mathrm{H}}_{\mathrm{reaction}}^{⊝}=-510.9 \mathrm{kJ} {\mathrm{mol}}^{-1} \\ \mathrm{Values} \mathrm{for} {\mathrm{S}}^{⊝}\mathrm{in} \mathrm{J} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}; \\ {\mathrm{Na}}_2{\mathrm{O}}_2\left(\mathrm{s}\right)=95.0 \\ \mathrm{Na}\left(\mathrm{s}\right)=51.2 \\ {\mathrm{O}}_2\left(\mathrm{g}\right)=205.0. \end{gathered}$$

 

Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to $3$ significant figures in $\mathrm{kJ} {\mathrm{mol}}^{-1}$, and in each case state whether or not the reaction is spontaneous under standard conditions.

$$\begin{gathered} \mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to {\mathrm{MgCl}}_2\left(\mathrm{s}\right); ∆{\mathrm{H}}_{\mathrm{reaction}}^{⊝}=-641.3 \mathrm{kJ} {\mathrm{mol}}^{-1} \\ \mathrm{Values} \mathrm{for} {\mathrm{S}}^{⊝}\mathrm{in} \mathrm{J} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}; \\ {\mathrm{MgCl}}_2\left(\mathrm{s}\right)=89.6 \\ \mathrm{Mg}\left(\mathrm{s}\right)=37.2 \\ {\mathrm{Cl}}_2\left(\mathrm{g}\right)=165. \end{gathered}$$

Calculate the standard Gibbs free energy of a given reaction, using the standard molar entropy values given. Express your answer to three significant figures $\mathrm{kJ} {\mathrm{mol}}^{-1}$, and in each case state whether or not the reaction is spontaneous under standard conditions.

$$\begin{gathered} {\mathrm{Ag}}_2{\mathrm{CO}}_3\left(\mathrm{s}\right)\to {\mathrm{Ag}}_2\mathrm{O}\left(\mathrm{s}\right)+{\mathrm{CO}}_2; ∆{\mathrm{H}}_{\mathrm{reaction}}^{⊝}=+167.5 \mathrm{kJ} {\mathrm{mol}}^{-1} \\ \mathrm{Values} \mathrm{for} {\mathrm{S}}^{⊝}\mathrm{in} \mathrm{J} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}; \\ {\mathrm{Ag}}_2\mathrm{O}\left(\mathrm{s}\right)=121.3 \\ {\mathrm{CO}}_2=213.6 \\ {\mathrm{Ag}}_2{\mathrm{CO}}_3\left(\mathrm{s}\right)=167.4. \end{gathered}$$

Methanol reacts with hydrogen bromide.

$$\begin{gathered} {\mathrm{CH}}_3\mathrm{OH}\left(\mathrm{l}\right)+\mathrm{HBr}\left(\mathrm{g}\right)\to {\mathrm{CH}}_3\mathrm{Br}\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right);∆{\mathrm{H}}^{⊝}=-46 \mathrm{kJ} {\mathrm{mol}}^{-1}. \\ \mathrm{Standard} \mathrm{molar} \mathrm{entropy} \mathrm{values}(\mathrm{in} \mathrm{J} {\mathrm{mol}}^{-1}{\mathrm{K}}^{-1}) \mathrm{are}: \\ {\mathrm{CH}}_3\mathrm{OH}\left(\mathrm{l}\right)=239.7, \mathrm{HBr}\left(\mathrm{g}\right)=98.6, {\mathrm{CH}}_3\mathrm{Br}\left(\mathrm{g}\right)=246.3, {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)=69.9 \\ \mathrm{Which} \mathrm{one} \mathrm{of} \mathrm{these} \mathrm{values} \mathrm{is} \mathrm{the} \mathrm{correct} \mathrm{values} \mathrm{of} ∆\mathrm{G} \mathrm{for} \mathrm{this} \mathrm{reaction} \mathrm{at} 25°\mathrm{C}? \end{gathered}$$

Calculate the standard Gibbs free energy change of reaction in the following reaction using the standard molar values for Gibbs free energy change given here. Comment on whether the reaction is Spontaneous or not, under standard conditions.

$2{\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{l}\right)\to 2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$

Values for

 $$\begin{gathered} {\mathrm{G}}^{⊝} \mathrm{in} \mathrm{kJ} {\mathrm{mol}}^{-1}; \\ {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)=-273.2 \\ {\mathrm{O}}_2\left(\mathrm{g}\right)=0(\mathrm{As} \mathrm{it} \mathrm{is} \mathrm{their} \mathrm{in} \mathrm{standard} \mathrm{states}) \\ {\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{l}\right)=-120.4. \end{gathered}$$

Calculate the standard Gibbs free energy change of reaction in the following reaction using the standard molar values for Gibbs free energy change given here. Comment on whether the reaction is Spontaneous or not, under standard conditions.

${\mathrm{NH}}_4{\mathrm{NO}}_3\left(\mathrm{s}\right)\to {\mathrm{N}}_2\mathrm{O}\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$

Values for

$$\begin{gathered} {\mathrm{G}}^{⊝} \mathrm{in} \mathrm{kJ} {\mathrm{mol}}^{-1}; \\ {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)=-273.2 \\ {\mathrm{N}}_2\mathrm{O}\left(\mathrm{g}\right)=+104.2 \\ {\mathrm{NH}}_4{\mathrm{NO}}_3=-184.0. \end{gathered}$$

Calculate the standard Gibbs free energy change of reaction in the following reaction using the standard molar values for Gibbs free energy change given here. Comment on whether the reaction is Spontaneous or not, under standard conditions.

$2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right)$

Values for

$$\begin{gathered} {\mathrm{G}}^{⊝} \mathrm{in} \mathrm{kJ} {\mathrm{mol}}^{-1}; \\ \mathrm{MgO}\left(\mathrm{s}\right)=-569.4 \\ \mathrm{Mg}\left(\mathrm{s}\right)=0 \\ {\mathrm{O}}_2\left(\mathrm{g}\right)=0. \end{gathered}$$

Calculate the standard Gibbs free energy change of reaction in the following reaction using the standard molar values for Gibbs free energy change given here. Comment on whether the reaction is Spontaneous or not, under standard conditions.

${\mathrm{C}}_3{\mathrm{H}}_8\left(\mathrm{g}\right)+5{\mathrm{O}}_2\left(\mathrm{g}\right)\to 3{\mathrm{CO}}_2\left(\mathrm{g}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Values for

$$\begin{gathered} {\mathrm{G}}^{⊝} \mathrm{in} \mathrm{kJ} {\mathrm{mol}}^{-1}; \\ {\mathrm{CO}}_2\left(\mathrm{g}\right)=-394.4 \\ {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)=-273.2 \\ {\mathrm{O}}_2\left(\mathrm{g}\right)=0 \\ {\mathrm{C}}_3{\mathrm{H}}_8\left(\mathrm{g}\right)=-23.4. \end{gathered}$$

Calculate the standard Gibbs free energy change of reaction in the following reaction using the standard molar values for Gibbs free energy change given here. Comment on whether the reaction is Spontaneous or not, under standard conditions.

$3 \mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)\to 3\mathrm{MgO}\left(\mathrm{s}\right)+2\mathrm{Fe}\left(\mathrm{s}\right)$

Values for

$$\begin{gathered} {\mathrm{G}}^{⊝} \mathrm{in} \mathrm{kJ} {\mathrm{mol}}^{-1}; \\ \mathrm{MgO}\left(\mathrm{s}\right)=-569.4 \\ \mathrm{Fe}\left(\mathrm{s}\right)=0 \\ \mathrm{Mg}\left(\mathrm{s}\right)=0 \\ {\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)=-742.2. \end{gathered}$$