Answer:
<u>A) Wood burning </u>
system : Wood.
surroundings : atmosphere
Enthalpy : Exothermic
<u>B) Water Freezing system </u>
System : Refrigerator
surroundings : water in the refrigerator
enthalpy change : Endothermic
<u>C) Sweat evaporating </u>
System : Human being
surroundings : Air nearby
Enthalpy change : exothermic
<u>D) Chemical Hand-warmer </u>
system : Hand warmer pack
Surroundings : human palms
Enthalpy Change : Exothermic
Explanation:
<u>A) Wood burning </u>
system : Wood
surroundings : atmosphere
Enthalpy : Exothermic
This system give away energy to its surroundings hence its enthalpy change is exothermic
<u>B) Water Freezing system </u>
System : Refrigerator
surroundings : water in the refrigerator
enthalpy change : Endothermic
The system absorbs heat from what is put inside(surroundings ) of it hence this is na endothermic system
<u>C) Sweat evaporating </u>
System : Human being
surroundings : Air nearby
Enthalpy change : exothermic
This is an exothermic reaction ( enthalpy change ) because the system gives out heat to the surrounding
<u>D) Chemical Hand-warmer </u>
system : Hand warmer pack
Surroundings : human palms
Enthalpy Change : Exothermic
There is movement of heat from the system to the surrounding hence it is an exothermic reaction