Question

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:Enthalpy Change:c.Sweat evaporatingSystem:Surroundings:Enthalpy Change:d.Chemical hand-warmerSystem:Surroundings:Enthalpy Change:

Answer 1

For burning wood, the system is the wood and oxygen, the surroundings is the air, and the reaction is exothermic. For water freezing, the system is the water molecules, the surroundings is the environment, and the reaction is endothermic. For sweat evaporating, the system is the sweat molecules, the surroundings is the air and skin, and the reaction is endothermic. For a chemical hand-warmer, the system is the chemicals inside, the surroundings is the air and surroundings, and the reaction is exothermic.

Step-by-step explanation:

For the wood burning process:

1. System: The wood and the oxygen in the combustion
2. Surroundings: The air and the objects around the burning wood
3. Enthalpy Change: Exothermic reaction, as heat is released into the surroundings.

For the water freezing process:

1. System: The water molecules
2. Surroundings: The environment and the objects around the water
3. Enthalpy Change: Endothermic reaction, as heat is absorbed from the surroundings.

For the sweat evaporating process:

1. System: The sweat molecules
2. Surroundings: The air and the skin
3. Enthalpy Change: Endothermic reaction, as heat is absorbed from the surroundings.

For the chemical hand-warmer process:

1. System: The chemicals inside the hand-warmer
2. Surroundings: The air and the objects surrounding the hand-warmer
3. Enthalpy Change: Exothermic reaction, as heat is released into the surroundings.

Answer 2

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

Step-by-step 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