HCl (aq) + NaOH (aq) -> NaCl (aq) + H2O (l)
Will the neutralisation reaction be endothermic or exothermic? Hint: think about the net ionic equation.
So, taking the hint, I got: OH- + H+ -> H2O
Not sure how that helps, and now I'm stuck; how would I figure out if this is endothermic or exothermic?
My teacher was also saying something about turning something reactive, stable. And then that would be an exothermic reaction because... (didn't catch the next part). I don't know if that's relevant or if it helps at all, but yeah.
On a side note and kind of irrelevant to this question (but still chemistry related), my teacher was saying something along the lines of, "higher enthalpy products require more energy; the reaction would be endothermic". I feel like I heard wrong; shouldn't the reaction be exothermic then?? Since more energy was used to make bonds resulting in more energy released..? If I did hear right, could you please explain?
I have looked all over the net and I can't find the value for delta H for H^+ + OH^- ==> H2O but I know it is exothermic. All neutralization reactions are exothermic; some more than others.
I remember this from last year - you should have a table of the heat of enthalpy somewhere in your book. From this you'll need to get the values of delta H (heat) of each mixture. The left side (HCl + NaOH) is the reaction and the right side is the result - you'll learn why later on. Calculate the total delta H of the reaction and subtract the total delta H of the product from it. If you get a positive value, it radiates heat which means it's exothermic. If it is negative, heat is needed to get a reaction so it is endothermic.
To determine whether the neutralization reaction is endothermic or exothermic, you can consider the energy changes in the reaction. In this case, the reaction is between hydrochloric acid (HCl) and sodium hydroxide (NaOH) to form sodium chloride (NaCl) and water (H2O).
The net ionic equation you provided, OH- + H+ -> H2O, represents only the essential particles involved in the reaction. It shows the neutralization of the hydroxide ion (OH-) with a hydrogen ion (H+) to form water (H2O).
In general, the formation of water from its constituent ions is an exothermic process because energy is released when new bonds are formed. This is because the new bonds in water are more stable than the original bonds in the reactants.
Therefore, based on this information, the neutralization reaction between HCl and NaOH is exothermic.
Regarding your additional question about higher enthalpy products and energy requirements, it seems that there might have been a misunderstanding. In general, higher enthalpy products require less energy to form because they are more stable. If your teacher mentioned that the reaction would be endothermic based on higher enthalpy products requiring more energy, it might have been a mistake. It is more accurate to say that reactions with higher enthalpy products are typically exothermic.
To determine if the neutralization reaction (HCl + NaOH -> NaCl + H2O) is endothermic or exothermic, we can examine the chemical bonds being formed and broken during the reaction.
In the reaction, the hydrogen ion (H+) from the acid (HCl) combines with the hydroxide ion (OH-) from the base (NaOH) to form water (H2O). This can be represented by the net ionic equation: OH- + H+ -> H2O.
By looking at this equation, we can see that two chemical bonds are being formed: one between the hydrogen ion (H+) and hydroxide ion (OH-) to form water (H2O). Breaking and forming chemical bonds involve energy changes. When a bond is formed, energy is released (exothermic), and when a bond is broken, energy is absorbed (endothermic).
In this case, the bond formation between H+ and OH- to form H2O is exothermic because energy is released. The neutralization reaction overall results in the formation of water, which is more stable compared to the reactants.
Now, addressing your side note question about the relationship between higher enthalpy products and endothermic reactions, your understanding is correct.
In general, if the formation of products requires more energy compared to the breaking of reactant bonds, the reaction is endothermic. This is because energy is absorbed to break the bonds, resulting in an overall energy increase in the system. On the other hand, if the formation of products releases more energy compared to the breaking of reactant bonds, the reaction is exothermic. This is because energy is released during the formation of bonds, resulting in an overall energy decrease in the system.
So, when your teacher mentioned that "higher enthalpy products require more energy; the reaction would be endothermic," they may have been referring to a different scenario or concept. In the context of the net ionic equation and the neutralization reaction between HCl and NaOH, the reaction is exothermic because bond formation between H+ and OH- releases energy.