Topic by Batavian

  • Batavian
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Topic

A pork roast must absorb 1600 kJ to fully cook, and if only 14% of the heat produced by the barbeque is actually absorbed by the roast.

The propane fuel used in gas barbeques burns according to the following thermochemical equation:
C3H8(g)+502(g)--->3CO2(g)+4H2O(g)

Hrxn= -2217kJ

  Reply by Norm

  • Norm
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What mass of CO2 is emitted into the atmosphere during the grilling of the pork roast

Heat absorbed by Pork roast for each mole of propane = 0.14 x 2217kJ = 310.4kJ

# of moles of propane needed = 1600kJ / 310.4kJ = 5.155moles

Accroding to the balanced equation, 1 mol of C3H8 produces 3 moles of CO2 so, 5.155 moles C3H8 produces: 3 x 5.155 mol of CO2 = 25.775 moles CO2

Moles = mass/MW
mass = MW x mole = 44g/mol x 25.775mol =1134g of CO2 emitted