Question

The world burns approximately 3.8×1012 kg of fossil fuel per year.

Part A:

Use the combustion of octane as the representative reaction and determine the mass of carbon dioxide (the most significant greenhouse gas) formed per year.

Express your answer to two significant figures and include the appropriate units.

Part B:

The current concentration of carbon dioxide in the atmosphere is approximately 380 ppm (by volume). By what percentage does the concentration increase each year due to fossil fuel combustion? Approximate the average properties of the entire atmosphere by assuming that the atmosphere extends from sea level to 15 km and that it has an average pressure of 381 torr and average temperature of 275 K. Assume Earth is a perfect sphere with a radius of 6371 km.

Express your answer to two significant figures and include the appropriate units.

Answer 1

Mass molar → 228.16g/mol 703.84g/mol 2C3H18 + 250216CO2 + 18H20 Mass → 3.8x1012Kg ? (PART A) Mass molar expressed in Kg C8H18 = 0.22816 Kg/mol CO2 = 0.70384 Kg/mol 3.8x1012 Kg CsH18 0.70384 Kg CO2 = 1.1722x1013 Kg CO2 (mass formed by octane combustion per year) 10.22816 Kg CsH18 (PART B) V sphere = 4/39R3 (R = Radius) V atmosphere earth = (4/3) (3.1416) (6371Km)3 = 1.0832x1012 Km2 1x1012 L = 1.0832x1024 L 1 Km PV = nRT →n= PV/RT nCO2 = (381 Torr) (1.0832x1024) = 2.4064X1022 moles (62.36367 L Torf/K'mol) (275K) nCO2= mass/Molar mass → mass = (n) (Molar mass) = (2.4064X1022 moles) (43.99g/mol) = 1.0585x1024g mgCO2 = gx 1000 = (1.0585x1024g) (1000) = 1.0585x1027mg ppmCO2 = mg CO2/L (Vatmosphere earth) = 1.0585x1027mg/1.0832x1024 L = 977.27ppm 380ppm CO2 represent 100% 977.27ppmCO2) 100% = 257.1763% (percentage of concentration CO2 increased each year) 380ppmCO2