A 114g sample of sucrose undergoes incomplete combustion according to the reaction
C12H22011 + 5O2 ---> 4C + 6CO + 2CO2 + 11H2O
using the chart of enthalpies of formation determine the enthalpy released by the sample
i think that it is a simple enthalpy problem but in the chart of enthalpies the enthalpy of C12H22O11 is not given, so how am i supposed to answer the question?! thanks for any help!
It is given here; you can skip a lot of the reading until the approximately 2000 kJ/mol is given.
http://www2.ucdsb.on.ca/tiss/stretton/CHEM2/enthal11.htm
thank you very much
To determine the enthalpy released by the sample, you will need to use the principle of Hess's Law, which states that the total enthalpy change of a reaction is independent of the pathway taken.
In this case, since the enthalpy of formation for C12H22O11 is not given in the standard enthalpy of formation chart, you will need to use other available enthalpies of formation to calculate the enthalpy change of the reaction.
Here are the steps to solve the problem:
1. Start by writing the balanced equation for the reaction:
C12H22011 + 5O2 ---> 4C + 6CO + 2CO2 + 11H2O
2. Break down the reaction into smaller steps, if possible, by comparing it to other known reactions that have enthalpy values listed. For example, you can break down the reaction as follows:
C12H22011 + 6O2 → 12CO + 11H2O (Step 1)
CO + O2 → CO2 (Step 2)
C + 2O2 → CO2 (Step 3)
3. Now, identify the known enthalpies of formation for the products and reactants involved in the smaller steps. The enthalpies of formation can be found in the enthalpy table.
4. Calculate the enthalpy change for each of the smaller steps using the known enthalpies of formation. Recall that the enthalpy change of a reaction equals the sum of the enthalpies of formation of the products minus the sum of the enthalpies of formation of the reactants.
5. Finally, sum up the individual enthalpy changes of each step to find the overall enthalpy change for the original reaction. Since enthalpy is a state function, the overall enthalpy change will be the same regardless of the pathway taken.
By following these steps, you can still calculate the enthalpy change of the reaction using other known enthalpies of formation, even if the enthalpy of formation for C12H22O11 is not given in the standard chart.