The question is "Under what circumstances are delta E & delta H essentially equal. Using the equation delta H = delta E + PV. Delta E & H will essentially be equal when there is no change in volume. This part I understand, but the solutions manual adds
"Delta H & delta E are nearly equal when there are no gases in a chemical reaction..." Why is it only with gases? In a reaction, solids and liquids also change forms (like ice to water) & have a change in volume. So am I just getting confused with concepts, or is the book trying to point out something I'm not seeing?