When an ice cube melts in your hand, it changes from a solid to a liquid.
H2O (s) → H2O (l)
This is an example of ________________ reaction, because heat is _____________ the system.
a
endothermic; entering
b
exothermic; leaving
c
endothermic; leaving
d
exothermic; entering
c) endothermic; leaving
The correct answer is choice a: endothermic; entering.
In an endothermic reaction, heat is absorbed from the surroundings and enters the system. This is observed when an ice cube melts in your hand. As the ice cube absorbs heat from your hand, it undergoes a phase change from solid (ice) to liquid (water). Therefore, the reaction is endothermic, and heat is entering the system.
The correct answer is c) endothermic; leaving.
In this scenario, when an ice cube melts in your hand, it absorbs heat from your hand, causing the ice to change from a solid to a liquid. This process is known as an endothermic reaction.
To determine whether it is an endothermic or exothermic reaction, you need to understand the definitions of these terms.
An endothermic reaction is a process in which heat is absorbed from the surroundings, leading to an increase in the energy of the system. For the ice cube to melt, it needs to absorb heat, which it obtains from your warm hand.
On the other hand, an exothermic reaction is a process in which heat is released to the surroundings, resulting in a decrease in the energy of the system. An example of an exothermic reaction is when a fuel burns, releasing heat into the surroundings.
In the given scenario, since the ice cube absorbs heat from your hand to melt, it is an endothermic reaction. The heat is leaving the surroundings (your hand), which corresponds to the option c) endothermic; leaving.