When water evaporates at constant pressure, the sign of the change in enthalpy:

A. is negative.

B. is positive.

C. depends on the temperature.

D. depends on the volume of the container.

E. does not exist; that is, the enthalpy change is zero.

B. is positive H20 (l)--> H20 (g) when that happens, the heat is absorbed into the liquid to change the state of the liquid to gas; therefore, in order to change to a gaseous state, heat must be a reactant. and so enthalpy is increasing

Answered by Hshin7 | 2024-06-10

The sign of the change in enthalpy when water evaporates at constant **pressure **is positive, as it is an endothermic process where heat is absorbed, and the enthalpy of vaporization is greater than that of fusion. ;

Answered by Elsa2212 | 2024-06-18

When water evaporates, it absorbs heat from its surroundings, leading to a positive change in enthalpy. Thus, the correct answer is B: positive.
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Answered by Hshin7 | 2024-10-15