Question

Identify each process as endothermic or exothermic and indicate the sign of H . (a) an ice cube melting (b) nail polish remover quickly evaporating after it is accidentally spilled on the skin (c) gasoline burning within the cylinder of an automobile engine

Answer 1

Answer:an ice cube melting ∆H=+ve

nail polish remover quickly evaporating after it is accidentally spilled on the skin ∆H=-ve

gasoline burning within the cylinder of an automobile engine ∆H=-ve

Explanation:

In an endothermic process, such as the melting of an ice cube, heat is absorbed from the surrounding. The enthalpy change is positive. The evaporation a nail polish and burning of gasoline are exothermic processes which lead to the release of heat to the surrounding. The sign of the enthalpy change in both cases is negative.