-maltose can be hydrolysed to glucose according to the following reaction:<br><br>The standard entha — Thermodynamics and Thermochemistry Chemistry Question
Question
$\alpha$-maltose can be hydrolysed to glucose according to the following reaction:<br>$\alpha\text{-C}_{12}\text{H}_{22}\text{O}_{11}\text{(aq)} + \text{H}_2\text{O(l)} \to 2\text{C}_6\text{H}_{12}\text{O}_6\text{(aq)}$<br>The standard enthalpy of formation of $\text{H}_2\text{O(l)}$, $\text{C}_6\text{H}_{12}\text{O}_6\text{(aq)}$ and $\alpha\text{-C}_{12}\text{H}_{22}\text{O}_{11}\text{(aq)}$ are $-285, -1263$ and $-2238\text{ kJ/mol}$, respectively. Which of the following statement(s) is/are true?
💡 Solution & Explanation
$\Delta H_{\text{hydrolysis}} = 2(-1263) - (-2238 - 285) = -2526 + 2523 = -3\text{ kJ}$. As it is negative, it is exothermic. Applying Hess's law to combustion evaluates the heat of maltose combustion as 3 kJ less than the combustion of 2 moles of glucose.