If you mixed water and dilute sulfuric acid, rather than concentrated sulfuric acid, would the exothermic reaction be greater or less than the exothermic reaction that occurs during hydration of a concentrated sulfuric acid? If so, why?
Less if you mix water and dilute H2SO4 because some of the energy has already been emitted. See my later post about the dangers of adding water to conc H2SO4.
To determine whether the exothermic reaction of mixing water and dilute sulfuric acid would be greater or less than the exothermic reaction during the hydration of concentrated sulfuric acid, we need to consider the concentration and the amount of heat released during the reactions.
When concentrated sulfuric acid is diluted with water, a highly exothermic reaction occurs. This is because sulfuric acid is a strong acid that readily dissociates into ions when it comes into contact with water. The hydration of sulfuric acid involves the addition of water molecules to the acid, resulting in the release of a large amount of heat.
On the other hand, if you mix water and dilute sulfuric acid, the reaction would still be exothermic, but typically less so than when using concentrated sulfuric acid. Dilute sulfuric acid already contains a higher percentage of water compared to concentrated sulfuric acid, which means there is a lower concentration of sulfuric acid molecules available for the reaction. Consequently, the amount of heat released during the reaction is usually less compared to the hydration of concentrated sulfuric acid.
However, it is important to note that the extent of the exothermic reaction also depends on the specific concentrations and quantities of water and sulfuric acid used. The exact values can be determined by conducting experiments and measuring the heat released during the reactions.