Chemical Thermodynamics — Chemistry STD 12 Science — Question
Maharashtra BoardEnglish MediumSTD 12 ScienceChemistryChemical Thermodynamics2 Marks
Question
What are the conditions under which $\Delta H =\Delta U$ ?
✓
Answer
1. For any thermodynamic process or a chemical reaction at constant volume, $\Delta V =0$. 2. Since $\Delta H=\Delta U+P \Delta V$, at constant volume $\Delta H=\Delta U$. 3. In the reactions, involving only solids and liquids, $\Delta V$ is negligibly small, hence $\Delta H =\Delta H$. 4. In a chemical reaction, in which number of moles of gaseous reactants and gaseous products are equal, then change in number of moles, $\Delta n=n_2-n_1=0$. Since $\Delta H=\Delta U+$ $\Delta n R T$, as $\Delta n=0, \Delta H=\Delta U$.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.