use standard enthalpies of formation to calculate delta Hrxn for the following reaction. 2H2S(g)+3O2(g)-->2H2O(l)+2SO2(g) express the answer using four significant figures
Delta Hrxn = ? kJ
DHfrxn = (n*DHf products)-(n*DHf reactants)
Look up DHf values in your text or notes.
we dnt take notes that's why im so lost
Then look in your text. Most texts have a set of delta Hof values.
And I might suggest you take notes. You can't possibly remember everything.
honestly all we do is labs during class i would love to take notes
Do you have a table in your text? I may be able to find a table on the web or I can look up some values if your text doesn't have them listed.
To calculate the standard enthalpy change (ΔHrxn) for a reaction using the standard enthalpies of formation, you need to follow these steps:
Step 1: Write down the balanced chemical equation for the reaction. In this case, the balanced equation is:
2H2S(g) + 3O2(g) → 2H2O(l) + 2SO2(g)
Step 2: Identify the standard enthalpies of formation (ΔHf°) for each compound involved in the reaction. These values can be found in a standard enthalpy of formation table. Here are the values for the compounds in question:
ΔHf° for H2S(g) = -20.6 kJ/mol
ΔHf° for O2(g) = 0 kJ/mol
ΔHf° for H2O(l) = -285.8 kJ/mol
ΔHf° for SO2(g) = -296.8 kJ/mol
Step 3: Calculate the ΔHrxn using the formula:
ΔHrxn = ΣΔHf°(products) - ΣΔHf°(reactants)
For the products, we have:
2H2O(l) with a coefficient of 2, so the contribution to ΔHrxn is: 2 * (-285.8 kJ/mol)
2SO2(g) with a coefficient of 2, so the contribution to ΔHrxn is: 2 * (-296.8 kJ/mol)
For the reactants, we have:
2H2S(g) with a coefficient of 2, so the contribution to ΔHrxn is: 2 * (-20.6 kJ/mol)
3O2(g) with a coefficient of 3, so the contribution to ΔHrxn is: 3 * (0 kJ/mol)
ΔHrxn = [2 * (-285.8 kJ/mol)] + [2 * (-296.8 kJ/mol)] - [2 * (-20.6 kJ/mol)] - [3 * (0 kJ/mol)]
Simplifying the equation:
ΔHrxn = -571.6 kJ/mol - 593.6 kJ/mol + 41.2 kJ/mol
ΔHrxn = -1124.0 kJ/mol
Therefore, the value of ΔHrxn for the reaction 2H2S(g) + 3O2(g) → 2H2O(l) + 2SO2(g) using four significant figures is -1124.0 kJ.