Take the entropy, $S$, of $\text{H}_2\text{O}$ to be zero at $0\,\text{K}$. On the axes, sketch how the entropy of $\text{H}_2\text{O}$ varies from $0\,\text{K}$ to $300\,\text{K}$.
Put one tick (✓) in each line of the table to indicate the sign of the entropy changes, $\Delta S$. (i) solid dissolving in water, (ii) water boiling to steam.
The reaction that forms methanol is shown here: $\text{CO}_2(g) + 3\text{H}_2(g) \rightarrow \text{CH}_3\text{OH}(g) + \text{H}_2\text{O}(g)$. Use suitable bond energies from the Data Booklet to Calculate the enthalpy change, $\Delta H$, for this reaction in the gas phase.
At $298\,\text{K}$, both products in this reaction are liquid. $\text{CO}_2(g) + 3\text{H}_2(g) \rightarrow \text{CH}_3\text{OH}(l) + \text{H}_2\text{O}(l)$, $\Delta H^\circ = -131\,\text{kJ mol}^{-1}$. The table gives standard entropies. Calculate the standard entropy change, $\Delta S^\circ$, for this reaction.
Calculate the standard Gibbs free energy change, $\Delta G^\circ$, for this reaction at $298\,\text{K}$.
Predict the effect of increasing the temperature on the feasibility of this reaction.
In a methanol-oxygen fuel cell, $\text{CH}_3\text{OH}(l)$ and $\text{O}_2(g)$ are in contact with two inert electrodes dipped into an acidic solution. The half-equation for the reaction at the methanol electrode is: $\text{CH}_3\text{OH} + \text{H}_2\text{O} \rightleftharpoons \text{CO}_2 + 6\text{H}^+ + 6e^- \qquad E^\circ = -0.02\ \text{V}$ Use the Data Booklet to write an equation for the overall cell reaction.
Use the $E^\circ$ values to calculate $E^\circ_{\text{cell}}$ for this reaction.