Why is this reaction considered exothermic?
"Concentrated sulfuric acid dissolves in water and the solution becomes warmer."
This is a homework question and when I answered the problem, I thought it was endothermic because the solution is gaining heat, but when my professor went over the problems in class, he said it was exothermic. Can someone please explain to me why this is considered exothermic?
In order to determine whether a reaction is exothermic or endothermic, we need to consider the changes in energy during the reaction. Exothermic reactions release energy, usually in the form of heat, resulting in an increase in temperature of the surroundings. Endothermic reactions, on the other hand, absorb energy from the surroundings, causing a decrease in temperature.
In the case of concentrated sulfuric acid dissolving in water, the reaction is indeed exothermic. Here's why:
When concentrated sulfuric acid is mixed with water, it undergoes a chemical reaction in which water molecules surround the individual acid molecules, breaking them apart into ions (H+ and SO4^2-). This process is called hydration.
The energy released during this hydration process is greater than the energy needed to break the initial interactions between the sulfuric acid molecules. As a result, energy is released into the surrounding environment, which manifests as an increase in temperature. In other words, heat is generated.
So, when the question states that "the solution becomes warmer," it implies that heat is being released during the reaction, indicating an exothermic process.
To summarize, the concentrated sulfuric acid dissolving in water is considered an exothermic reaction because energy is being released into the surroundings, resulting in a temperature increase.
The reaction between concentrated sulfuric acid and water is considered exothermic because it releases heat energy into the surroundings. In an exothermic reaction, the products have less energy than the reactants, resulting in a net release of energy.
In this case, when concentrated sulfuric acid dissolves in water, the chemical bonds in the reactants are broken, and new bonds are formed to produce the products. This process releases energy in the form of heat. As a result, the temperature of the solution increases, indicating that thermal energy is being released to the surroundings.
Even though the solution gains heat, the term "exothermic" describes the overall net heat release of the reaction. In an exothermic reaction, the energy released from the reaction exceeds the heat absorbed by the reactants. So, in this case, the heat released during the dissolution of sulfuric acid into water is greater than the heat absorbed by the solution, making it an exothermic reaction.