For each of the environments below: (1) identify your system and surroundings and (2) predict whether it would be endothermic or exothermic. a.Wood burningSystem:Surroundings:Enthalpy Change:b. Water freezingSystem:Surroundings:Enthalp y Change:c. Sweat evaporatingSystem:Surroundings:Enth alpy Change:d. Chemical hand-warmerSystem:Surroundings:Enth alpy Change:

A) Wood burning

system : Wood.

surroundings : atmosphere

Enthalpy : Exothermic

B) Water Freezing system

System : Refrigerator

surroundings :  water in the refrigerator

enthalpy change : Endothermic

C) Sweat evaporating

System :  Human being

surroundings : Air nearby

Enthalpy change : exothermic

D) Chemical Hand-warmer

system : Hand warmer pack

Surroundings : human palms

Enthalpy Change : Exothermic

Explanation:

A) Wood burning

system : Wood

surroundings : atmosphere

Enthalpy : Exothermic

This system give away energy to its surroundings hence its enthalpy change is exothermic

B) Water Freezing system

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

C) Sweat evaporating

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

D) Chemical Hand-warmer

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

"hydrogen bonding is the attraction of h atoms in the water molecule (slight + charge) to o atoms in a neighboring water molecule (slight - charge); it is a weak interatomic force. but it is still strong enough to the water molecules "stick" together."