The question: A typical frostless refrigerator uses 655 kWh of energy per year i

Question

The question:
A typical frostless refrigerator uses 655 kWh of energy per year inthe form of electricity. Suppose that all of this electricity isgenerated at a power plant that burns coal containing 3.2% sulfurby mass and that all of the sulfur is emitted as SO2when the coal is burned. If all of the SO2 goes on to reactwith rainwater to form H2SO4, what mass ofH2SO4 is produced by the annual operation ofthe refrigerator? (Hint: Assume that the remaining percentage ofthe coal is carbon and begin by calculating Hrxnfor the combustion of carbon.) Ok I understand that 655 kWh converts to3.6*10^6 J or 3600 kJ. and I write the equation for the combustionof carbon: C + O2 --> CO2 I find the Hrxn for the combustion ofcarbon, and i get -393.5 kJ Now I am not sure where to go from here. Thanks The question:
A typical frostless refrigerator uses 655 kWh of energy per year inthe form of electricity. Suppose that all of this electricity isgenerated at a power plant that burns coal containing 3.2% sulfurby mass and that all of the sulfur is emitted as SO2when the coal is burned. If all of the SO2 goes on to reactwith rainwater to form H2SO4, what mass ofH2SO4 is produced by the annual operation ofthe refrigerator? (Hint: Assume that the remaining percentage ofthe coal is carbon and begin by calculating Hrxnfor the combustion of carbon.) Ok I understand that 655 kWh converts to3.6*10^6 J or 3600 kJ. and I write the equation for the combustionof carbon: C + O2 --> CO2 I find the Hrxn for the combustion ofcarbon, and i get -393.5 kJ Now I am not sure where to go from here. Thanks I find the Hrxn for the combustion ofcarbon, and i get -393.5 kJ Now I am not sure where to go from here. Thanks

Explanation / Answer

I'm actually working on this same problem, and haven't quitefigured it out either. So far what I have after you find that the H ofCO2 -393.5, you can then divide that by the percent ofCarbon that is in the coal. For me it is 96.5%, for you I thinkit's 96.8. That will give you the total H for both C and S,and you can multiply that by the percent of S, (.032) and find thatthe H of S + O2 --> SO2. For me, itis -14.272 kJ, your's will be slightly different. Then I write an equation to have that SO2 react withrainwater (H2O), and form H2SO4,which is exactly what the problem says. There's just one problemwith this though, that reaction can't be balanced, so I don't knowwhat to think of that. Probably that I'm doing it wrong, unless forsome reason rainwater has an extra oxygen in it. Anyway, I stillfound that Hrxn using the SO2 value andgot -513.9 kJ. Then I converted the 655 kWh to kJ and got 2358000, which Iconverted to moles using 1mol/513.9 kJ, then converted from molesto grams using 1 g/98.046 mol, and got 4.499 x 105 gramsof H2SO4, which was incorrect. I think myproblem is that my equation isn't balanced, but there could besomething else as well.

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