Which event is an example of an exothermic reaction?
a
melting ice
b
evaporation
c
combustion
d
decomposition
c - combustion
The correct answer is "c) combustion."
To determine if an event is an example of an exothermic reaction, we need to understand what an exothermic reaction is.
An exothermic reaction is a chemical reaction that releases energy in the form of heat or light. It usually generates heat, causing the temperature of the surroundings to increase.
Let's go through the options to determine which one is an example of an exothermic reaction:
a) Melting ice: Melting ice is a phase change that absorbs heat from the surroundings to convert solid ice into liquid water. It is an endothermic process because it requires an input of energy to occur, rather than releasing energy. So, it is not an example of an exothermic reaction.
b) Evaporation: Evaporation is also an endothermic process. It occurs when a liquid changes into a gas, and it requires energy to break the intermolecular forces holding the liquid together. This process cools the surroundings, rather than heating them. So, it is not an example of an exothermic reaction.
c) Combustion: Combustion is the process of rapid oxidation, particularly the reaction of a substance with oxygen. It releases heat and light as energy, making it an example of an exothermic reaction. So, combustion is the correct example of an exothermic reaction.
d) Decomposition: Decomposition is the breakdown of a compound into simpler substances. While there are different types of decomposition reactions, they can be either endothermic or exothermic, depending on the specific reaction. Without additional information, it is difficult to determine if it is an example of an exothermic reaction.
In conclusion, the event "c) combustion" is the best example of an exothermic reaction because it involves a rapid oxidation process that releases heat and light energy.