Adblocker Detected
We always struggled to serve you with the best online calculations, thus, there's a humble request to either disable the AD blocker or go with premium plans to use the AD-Free version for calculators.
Disable your Adblocker and refresh your web page 😊
Table of Content
The enthalpy calculator is specially designed to calculate the exact amount of energy generated in an exothermic or endothermic reaction.
“Enthalpy is the measure of the total energy released or absorbed in a thermodynamic system”
Whenever a system changes its state from solid to liquid (the latent heat of fusion) or liquid to gas (the latent heat of vaporization), it requires a sufficient intake of energy to produce a comprehensive change in entropy.
According to System International (SI), the entropy is expressed in joule per kilogram or simply joule.
At a constant temperature and pressure, the enthalpy equation for a system is given as follows:
where;
the enthalpy equation is as follows;
“ΔH° of reaction = ∑ΔH°f(products) – ∑ΔH°f(reactants)”
where;
However, the Heat Specific Calculator will allow us to determine the specific heat, mass of substance, and initial and final energy of any substance.
Using Hess’s Law evaluate the enthalpy of formation, ΔHfo, of FeCl3(s) from changes in enthalpy of the following two-step process that occurs under standard state conditions:
Fe(s)+Cl2(g)⟶ FeCl2(s)ΔH°= -258.69kJ
FeCl2(s)+3/2Cl2(g)⟶ FeCl3(s)ΔH°=−47.7kJ
Solution:
Need to focus on finding the enthalpy of the formation of FeCl3(s), which is equal to ΔH° for the reaction:
Fe(s)+5/2Cl2(g)⟶ FeCl3(s) ΔHfo=?
By looking at the reactions, see that the overall enthalpy ΔHfo for FeCl3(s) is equal to the sum of two reactions with known ΔH values.
Fe(s)+Cl2(g)⟶ FeCl2(s) ΔH°= -258.69kJ
FeCl2(s)+3/2Cl2(g)⟶ FeCl3(s) ΔH°= −47.7kJ
Fe(s)+5/2Cl2(g)⟶ FeCl3(s) ΔHfo= -306.39
The enthalpy of formation, ΔHf, of FeCl3(s) is −306.39 kJ/mol.
The enthalpy and the heat changes at each step in the reaction and overall heat, ΔHf° within a few seconds.
Sr # . | Name of Substance | Symbolic Formula | Standard Enthalpy of Formation ‘ΔH’ |
1. | Potassium Chloride | KCl(s) | -435.9 |
2. | Potassium Chlorate | KClO3(s) | -391.4 |
3. | Sodium Chloride | NaCl(s) | -411.0 |
4. | Sodium Hydroxide | NaOH(s) | -426.7 |
5. | Zinc Sulphide | ZnS(s) | -202.9 |
6. | Zinc Oxide | ZnO(s) | -348.0 |
7. | Copper Sulphate | CuSO4(s) | -769.9 |
8. | Copper Oxide | CuO(s) | -155.2 |
9. | Calcium Dioxide | Ca(OH)2(s) | -986.6 |
10. | Water | H2O(l) | -285.8 |
11. | Chloroform | CHCl3(l) | -131.8 |
12. | Carbon Dioxide | CO2(g) | -393.5 |
13. | Hydrogen Sulphide | H2S(g) | -20.1 |
14. | Ammonia | NH3(g) | -46.2 |
15. | Sulphur Trioxide | So3(g) | -395.2 |
16. | Hydrochloric Acid | HCl(g) | -92.3 |
17. | Nitrogen Oxide | NO(g) | +90.4 |
18. | Nitrogen Dioxide | NO2(g) | +33.9 |
19. | Phosphorus Pentachloride | PCl5(g) | -398.9 |
20. | Phosphorus Trichloride | PCl3(g) | -306.4 |
21. | Sulphur Dioxide | SO2(g) | -296.1 |
From the source of Wikipedia: Characteristic functions, Physical interpretation, Relationship to heat, Heat of reaction, Specific enthalpy, Throttling, Compressors.
From the source of Libre Text: Enthalpy Change Accompanying a Change in State, Effect of Temperature on Enthalpy, The Enthalpy of Phase Transition.