1. Engineering
  2. Chemical Engineering
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Question: explain step by step please...

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Explain step by step. Please!
4. Based on the information provided below (and other information in your notes and textbook). Energy Source Formula Energy Content Carbon Intensity Natural gas (mostly methane) Petroleum (approx. formula) Coal (approx. formula) Alberta oil sands From Example 2.3 in Masters and Ela (2007) CH4 39 MJ/m3 (at STP) C2Ha 43 MJ/kg C135HgeO&NS 14,968 Btu/lb 105 gCO2/MJ -From Problem 2.7 in Masters and Ela (2007). Calculated from Dulongs formula: 0 145.44 C620.28 H +40.5 S 77.54 O where: Q energy content in Btu/Ib C, H,S,O represent the weight percent of carbon, hydrogen, sulfur, and oxygen a. Calculate the energy content (in MJ/mole), the carbon emissions (in carbon intensity (in gc/MJ) for natural gas, petroleum, and coal. (For coal, assume that the combustion products are CO2, H2O, NO, SO2) b. Calculate the carbon intensity for the Alberta oil sands (in gC/MJ) c. Briefly describe why natural gas is often referred to as a clean form of energy d. Briefly describe why carbon intensity of the Alberta oil sands was being discussed in the debate about the proposed construction of the Keystone pipe line.

(b) If each kilogram of CFC-11 could be replaced by 1 kg of HCFC-22, by what percentage would the mass of chlorine emissions be reduced? Suppose total world energy consumption of fossil fuels, equal to 3 × 1017 kJ/yr, were to be obtained entirely by combustion of petroleum with the approximate chemical formula C2H3. Combustion of petroleum releases about 43 x 103 kJ/kg (a) Estimate the emmisions of CO2 per year. Q. 7temperature and pressure (STP), corresponding to 0°C and 1 atm. 760 mm of 101.3 kPa),d mole of an ideal gas occupies 22.4 L, or 0.0224 m3 and con- tains 6.02 x 1023 molecules Let us demonstrate the e usefulness of Avogadros hypothesis for gases by apply- ing it to a very modern concern; that is, the rate at which we are pouring carbon dioxide into the atmosphere as we burn up our fossil fuels. a3 EXAMPLE 3 Carbon Emissions from Natural Gas Worldwide combustion of methane, CH4 (natural gas), provides about 10.9x 1016 kJ of energy per year. If methane has an energy content of 39 × 10 (at STP), what mass of CO2 is emitted into the atmosphere each year? Also, express that emission rate as metric tons of carbon (not CO2) per year. A metric ton, which is 1,000 kg, is usually written as tonne to distinguish it from the 2,000-lb American, or short, ton. 3 kJ/m3 Solution We first need to express that consumption rate in moles, Converting kJ of energy into moles of methane is straightforward: 10.9 x 1016 kJlyr 39 X 10 kJ/m2,4x 103 mmoi 12.5 X 1013 mollyrEnvironmental Chemistry We know from the balanced chemical reaction given in (1) that each mole of CH yields 1 mole of CO2, so there will be 12.5 × 10 13 moles of CO2 emitted. Since the molecular weight of CO2 is 44, the mass of CO2 emitted is mass CO2 12.5 x 1013 molyr X 44 g/mol 5.5 x 1015 g/yr To express these emissions as tonnes of C per year, we must convert grams to tonnes and then sort out the fraction of CO2 that is carbon. The fraction of CO2 that is C is simply the ratio of the atomic weight of carbon (12) to the molecular weight of carbon dioxide (44): 1 kg 1 tonne12 g C C emissions 5.5 x 10s g COlyr 1,000 g 1,000 kg 44 g CO2 - 1.5 x 10 tonnes/yr 1.5 gigatonnelyr 1.5 GtClyr The 1.5 X 109 tonnes of carbon found in the preceding example is about 20 percent of the total, worldwide carbon emissions entering the atmosphere each ear when fossil fuels (coal, oil, natural gas) are burned. Global Atmospheric Change the main worry about these emissions is their potential to enhance the Earths greenhouse effect.

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