Question

Problem 3 (5 marks): The advantage of fossil fuels is that a lot of energy can be transported in a small amount of mass. The disadvantage is that their combustion produces CO2 (a greenhouse gas). a) Calculate how much energy is recoverable by the combustion of 1 g of octane. In a hydrogen-based economy, H2 could be produced collected and compressed so that it could be transported and burned like fossil fuels in car engines. b) How many grams of H2 gas are required to produce the same energy available in1 g of octane? H2 + O2>H20 (g) c) Some people have proposed that nuclear, solar or wind power could be used to power electrolysis to split water into H2 and O2. The H2 would then be collected and compressed for distribution to service stations. How much energy is required to produce the H2 from water and how much is required to compress the H2 to 3000 psi and cool it back down to 25 °C? d) Some people have proposed the catalytic oxidation of ammonia as a replacement for fossil fuels. How many grams of ammonia are required to replace the heat of combustion of 1 g of octane? 4 NH3 (g)7 O2->4 NO2 (g) 6 H20 (g) e) The NO2 gas produced by ammonia combustion must be stripped from the exhaust with the water produced to prevent acidification of the earth through acid rain. This requires that the water produced by the combustion first be condensed to liquid form. The exhaust can then be bubbled through the liquid water to strip out the NO2 in the form of nitrous acid by the reaction: NO2 (g) + H20 (l) + (aq)-> HNOs (aq)+ H+ How much combustion energy is lost to stripping the NO2 from the exhaust? Assume that the ΔΗ。TH+-> 0. Note, the proton concentration can only increase so much before no more NO2 can be absorbed, which means the scrubbing tank must be flushed periodically at the service station.

Answer 1

1t4 Nea 48.048 , 19868 mala Hz 241.82

Hear 043

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