Given information
The sign of enthalpy change of the given processes and the endothermic or exothermic nature of the process is to be determined.
a. natural gas burning on a stove
b. isopropyl alcohol evaporating from skin
c. water condensing from skin
Step-by-step explanation
a.
The given process of burning natural gas on the stove releases heat from the system to the surroundings. Since this process involves the release of heat.
Therefore, it is exothermic with negative value.
b.
The given process of evaporation of isopropyl alcohol absorbs heat from the surroundings. Since this process involves absorption of heat.
Therefore, it is endothermic with positive value.
c.
The given process of condensation of steam to form water releases heat from the system to the surroundings. Since this process involves the release of heat.
Therefore, it is exothermic with negative value.