4. Electrochemistry
A section of Chemistry, 5070
Listing 10 of 236 questions
Hydrogen reacts with oxygen as shown in the equation. 2H2+ O22H2OA sample containing 1.00 mol of hydrogen, H2, is completely combusted. This sample releases 286 kJ of heat energy. Calculate the heat energy released when 25.0 g of hydrogen is completely combusted. heat energy released kJ Use ideas about bond breaking and bond forming to explain why this reaction is exothermic. The reaction shown also represents the overall process that occurs within a hydrogen-oxygen fuel cell. Describe one advantage of using a hydrogen-oxygen fuel cell to power a motor vehicle rather than burning gasoline. Complete the equations for the two electrode reactions that happen in a hydrogen-oxygen fuel cell. H2 + 2e− O2 + 4H+ + 4e−
5070_s20_qp_22
THEORY
2020
Paper 2, Variant 2
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Questions Discovered
236