When magnesium hydrogen carbonate reacts with sulfuric acid, would you consider that an exothermic reaction because it forms CO2 (gas)?
It IS an exothermic reaction but I don't know that the release of CO2 is the reason. The entropy is +.
Just out of curiosity, how would you figure out the delta g if you didn't know the delta h? I don't think it is possible, is it? And also, can you explain how you knew it was exothermic?
I know it is exothermic because I've been there and done that and I know it gets hot.
You can look up delta G of products and reactants in tables and calculate delta Grxn BUT those values are based on knowing both delta H and delta S so I don't think that is a legitimate answer.
The only other two ways I know are (a) to know or measure the equilibrium constant, then use dG = -RTlnK or (b) know, calculate, or measure the Eo value for the reaction, then use
dG = -nFEo. Of course these should count only as ONE way because K values often are determined by using Eo values.
To determine whether the reaction between magnesium hydrogen carbonate and sulfuric acid is exothermic or not, we need to consider the energy changes involved.
First, let's understand the reaction that takes place:
Magnesium hydrogen carbonate (Mg(HCO3)2) reacts with sulfuric acid (H2SO4) to form carbon dioxide (CO2) gas, magnesium sulfate (MgSO4), and water (H2O):
Mg(HCO3)2 + H2SO4 â CO2 + MgSO4 + H2O
Now, to assess if the reaction is exothermic or not, we need to examine the energy changes.
During a chemical reaction, breaking bonds requires energy, and forming new bonds releases energy. If more energy is released during bond formation than is consumed during bond breaking, the reaction is exothermic. On the other hand, if more energy is consumed during bond formation than is released during bond breaking, the reaction is endothermic.
In the given reaction, we can infer that bond breaking occurs in both the reactants (Mg(HCO3)2 and H2SO4), while bond forming occurs in the products (CO2, MgSO4, and H2O).
The formation of carbon dioxide gas (CO2) involves the breaking of the chemical bond between carbon and oxygen in the hydrogen carbonate ion (HCO3^-). This bond breaking step consumes energy.
However, the reaction also results in the formation of new bonds: the formation of carbon-oxygen double bonds in CO2, the formation of magnesium-oxygen bonds in MgSO4, and the formation of hydrogen-oxygen bonds in water (H2O). These bond formations release energy.
To determine the net energy change of the reaction, we need to compare the energy consumed during bond breaking with the energy released during bond formation.
If the energy released during bond formation is greater than the energy consumed during bond breaking, the reaction is exothermic. However, if the energy consumed during bond breaking is greater than the energy released during bond formation, the reaction is endothermic.
To definitively determine whether the reaction is exothermic or endothermic, experimental data or thermochemical equations would be required.