Calculate the enthalpy of reaction from the standard enthalpies of formation of the reactant and product molecules.
2C2H6+7O2-->4CO2+6H20
I am using the back of my book for the standard enthalpies of formation, but cannot seem to find the HoF for C2H6?
My book lists -84.86 kJ/mol for the gas.
Calculate the enthalpy change for the reaction
NO(g) + O(g) --> NO2(g)
from the following data:
NO(g) + O3(g) --> NO2(g) + O2(g) ; ∆H = -198.9 kJ
O3(g) --> 1.5O2(g) ; ∆H = -142.3 kJ
O2(g) --> 2O(g) ; ∆H = 495.0 kJ
To calculate the enthalpy of reaction using standard enthalpies of formation, you need to know the standard enthalpies of formation of all the reactants and products involved in the reaction.
The standard enthalpy of formation (ΔHf°) is the change in enthalpy when one mole of a substance is formed from its elements in their standard states at a specific temperature and pressure.
Unfortunately, the standard enthalpy of formation for C2H6 (ethane) is not listed in the back of your book. However, you can try to find the ΔHf° for C2H6 online using reliable sources or chemical databases.
If you are unable to find the ΔHf° for C2H6, you can use other available information to indirectly calculate the enthalpy of reaction. One way to do this is by using the bond enthalpy values.
The bond enthalpy is the energy required to break the bond between two atoms in a molecule. You can find bond enthalpy tables for common bonds. Using these values, you can calculate the energy needed to break the bonds in the reactants and the energy released when new bonds are formed in the products. Then, subtract the energy required to break the reactant bonds from the energy released by forming the product bonds.
Keep in mind that this approach is an approximation and may give you a rough estimate of the enthalpy of reaction, but it won't be as accurate as using standard enthalpies of formation.
I hope this helps! Let me know if you have any other questions.
To calculate the enthalpy of reaction using standard enthalpies of formation, you need to know the standard enthalpies of formation (ΔHf) for each individual compound involved in the reaction. Standard enthalpies of formation are usually given in reference books or online resources.
In order to find the standard enthalpy of formation for C2H6 (ethane), you can try the following options:
1. Consult a chemistry textbook: Look for a table or appendix in your textbook that provides standard enthalpies of formation for common compounds. Some textbooks include these values in the appendix or within a section on thermodynamics.
2. Use an online database: There are several online databases that provide reliable values for standard enthalpies of formation. Examples include NIST Chemistry WebBook (https://webbook.nist.gov/chemistry/) and CRC Handbook of Chemistry and Physics (https://www.hbcpnetbase.com/).
3. Refer to your teacher or professor: If you are unable to find the information in your textbook or online, you can seek guidance from your instructor. They may be able to provide you with the standard enthalpy of formation for C2H6 or direct you to a reliable source.
Remember that standard enthalpies of formation are typically given in units of kilojoules per mole (kJ/mol). Once you have the values for the standard enthalpies of formation for all the compounds in the reaction (including C2H6, CO2, and H2O), you can calculate the enthalpy of reaction by applying Hess's Law or directly summing up the enthalpies of formation for the products and subtracting the enthalpies of formation for the reactants.