Question

identify each process as endothermic or exothermic and indicate the sign of delta h. sweat evaporating from skin. water freezing in a freezer and wood burning to create fire.

Answer 1

an exothermic process is one that release heat (i.e.- ∆H= negative) and an endothermic process is one that absorb heat (i.e.- ∆H= positive)

i) Sweat evaporating from skin - evaporation is a process that converts liquid into vapour which requires energy, hence, it is endothermic, ∆H= positive

ii) Water freezing in a freezer - conversion of a liquid to solid state involves release of energy, hence, it is exothermic ∆H= negative

iii) Wood burning to create fire - burning release enormous heat, hence it is exothermic, ∆H= negative