The reaction SO₂(g) + 2 H₂S(g) ⇌ 3 S(s) + 2 H₂O(g) is the basis of a suggested method for removal of SO₂ from power-plant stack gases. The standard free energy of each substance is given in Appendix C. (b) In principle, is this reaction a feasible method of removing SO₂?

Video transcript

Welcome back everyone. We're told that the reaction where two moles of calcium carbonate and two moles of sulfur dioxide gas reacts with one mole of oxygen gas which produces two moles of calcium sulfate and two moles of carbon dioxide gas can be used to remove sulfur dioxide gas from the gasses produced by industrial processes. Using standard free energy values given below is the reaction in principle a feasible method of removing sulfur dioxide gas. So for this reaction to be a feasible method of removing sulfur dioxide, we want the reaction to be spontaneous, meaning that we want to recall that for a spontaneous reaction, we should have a negative change in gibbs free energy. So we want to calculate for our change in gibbs free energy of our reaction by recalling that. We can calculate it by taking the standard Gibbs free energy of our formation of our products. Subtracted from the standard Gibbs Free energy of formation of our reactant. So we're going to do the work for that here below were given all the values So all we need to do is plug in and simplify. So we would say that our change in gibbs free energy of our reaction is equal to beginning with the some of the um Gibbs free energy of formation of our products. We have two products where we begin with two moles of calcium sulfate, multiplied by its gibbs free energy of formation of negative 1322.0 kg joules per mole. As given in the prompt, adding adding on to this, We have our second reactant where we have two moles of our carbon dioxide gas, multiplied by its free energy standard. Free energy change given in the prompt as negative 394.4 kg joules per mole. This completes the some of the free energy change of formation of our products. And now we're going to subtract this from the free energy change of formation of our reactant. Where we begin with our first reactant which is two moles of our calcium carbonate, Multiplied by calcium carbonates. Free energy change of formation given in the prompt as negative 1,129.1 killer jewels per this is then added on to the free energy change of our second reactant, which is our two moles of our sulfur dioxide gas, multiplied by sulfur dioxide gas. Is free energy change of formation given in the prompt as negative 0.1 kg joules per mole. And we can actually finish off our brackets here because if we look to our third reactive oxygen gas, we see that has a free energy change of formation equal to zero kg per mole. So it's just going to be ruled out from our calculation here. So we can say that our free energy change. Standard Free energy change of our reaction is equal to by simplifying our first bracket. We should get a result of negative 3432.8 and canceling out our units of moles were left with killing jewels. So we do the same thing for our free energy change of formation of our reactant. So we have units of kilograms left subtracting this from our brackets and red will be able to simplify our brackets in red too negative 2858.4 kg joules as the simplified version of our some of our free energy change of formation of our reactant. So taking the differences here, we get that the free energy change of our reaction is equal to a value of negative 574.4. So we do have a negative magnitude for our standard free energy change, meaning that our we can say therefore our reaction is spontaneous and feasibly removes sulfur dioxide gas. So this is going to be our final answer to complete this example is this highlighted statement here. I hope that everything I explained was clear. If you have any questions, please leave them down below and I'll see everyone in the next practice video