Equation 1- 2Ss+3O2g+2SO3gh1=?
Equation 2- 2Ss+2O2g+2SO2gh3=-594kj
Equation 3- 2SO2g+O2g+2SO3gh3=-198kj
Use Hess's law in your own words.
What's the question?
H2+ H3=H1
Hess's law states that the enthalpy change of a chemical reaction is independent of the pathway between the reactants and products. In other words, the overall enthalpy change of a reaction can be calculated by the sum of the enthalpy changes of a series of intermediate reactions.
To apply Hess's law, you need to ensure that the chemical equations you are working with are balanced and that the stoichiometric coefficients are appropriate. In this case, we have three equations:
Equation 1: 1-2Ss + 3O2g → 2SO3gh1
Equation 2: 2Ss + 2O2g → 2SO2gh3 (ΔH = -594 kJ)
Equation 3: 2SO2g + O2g → 2SO3gh3 (ΔH = -198 kJ)
The goal is to calculate the enthalpy change for Equation 1.
To use Hess's law, we will manipulate equations 2 and 3 in order to obtain the same reactants and products as in equation 1. Here's how we can do that:
Reverse equation 2 and multiply it by 2 to obtain:
-2SO2gh3 → 2Ss + 2O2g (ΔH = 1188 kJ)
Multiply equation 3 by 2 to obtain:
4SO2g + 2O2g → 4SO3gh3 (ΔH = -396 kJ)
Now, we can add up the modified equations to obtain the final equation:
-2SO2gh3 + 4SO2g + 2O2g + 2Ss + 2O2g → 2SO3gh1 + 4SO3gh3
Simplifying the equation gives us:
2Ss + 3O2g → 2SO3gh1 + 4SO3gh3
The sum of the enthalpy changes of the equations on the left side is equal to the sum of the enthalpy changes on the right side:
ΔH1 + ΔH2 + ΔH3 = ΔH1 + ΔH3 (since ΔH2 is not included in equation 1)
Therefore, the enthalpy change (ΔH1) for equation 1 can be calculated by:
ΔH1 = ΔH2 + ΔH3
= (-594 kJ) + (-198 kJ)
= -792 kJ
So, the enthalpy change for equation 1 is -792 kJ.