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Tasha
Lv 7
Tasha asked in Science & MathematicsChemistry · 1 decade ago

Need help with Enthalpy ?

If a pork roast must absorb 1700 kJ to fully cook, and if only 14% of the heat produced by the barbeque is actually absorbed by the roast, what mass of CO2 is emitted into the atmosphere during the grilling of the pork roast?

Could you please tell me the formula I would use and show the steps

1 Answer

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  • 1 decade ago
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    assume propane grilling, which has an enthalpy change of -2219kJ mol-1

    and 3 moles of CO2 breaks down per mole of propane.

    see referenced url for reaction eq.

    total propane moles used? 1700 KJ = 14% OF original juice --> original juice = 1700 KJ / 0.14. That gives you total power created. Use 2219KJ/mole to convert to # of moles. We want to have moles in top, so divide total power by 1700 KJ / 0.14. Now we know how many moles of propane, and we know 3 moles of CO2 = 1 mole of propane, so convert to moles of CO2. Convert to grams of CO2. Done.

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