Which chemical or physical change is an exothermic process?
A. the baking of cookies
B. a glass
C. the combustion of gasoline
D. the evaporation of water from a pool
E. the cold pack reaction [tex]$\left( NH _4 NO _3+ H _2 O +\right.$[/tex] heat [tex]$\rightarrow NH _4 OH + HNO _3$[/tex] )
Answer (1)
Baking cookies and evaporation of water are endothermic processes.
A glass is a material, not a process.
Cold pack reaction absorbs heat and is endothermic.
Combustion of gasoline releases heat and is an exothermic process, so the answer is t h eco mb u s t i o n o f g a so l in e .
Explanation
Analyzing the Options Let's analyze each option to determine which process releases heat, thus identifying the exothermic process.
Identifying Exothermic Process
The baking of cookies: Baking requires heat input, making it an endothermic process, not exothermic.
A glass: A glass is a material, not a process, so it cannot be classified as exothermic or endothermic.
The combustion of gasoline: Combustion is a process that releases heat and light, making it an exothermic process.
The evaporation of water from a pool: Evaporation requires heat input for the water to change from liquid to gas, making it an endothermic process.
The cold pack reaction ( N H 4 N O 3 + H 2 O + heat → N H 4 O H + H N O 3 ): This reaction absorbs heat, as indicated by 'heat' on the reactant side, making it an endothermic process.
Conclusion Based on the analysis, the combustion of gasoline is the only process that releases heat.
Examples
Exothermic reactions are crucial in many aspects of daily life. For instance, the combustion of fuels like gasoline in a car engine releases energy, enabling the car to move. Similarly, the burning of natural gas in a furnace provides heat for homes. Understanding exothermic processes helps us harness energy efficiently and safely in various applications, from transportation to heating.
