2h2(g)+o 2(> 2 h2o(g)if eight moles of hydrogen react how many of moles of water are produced and how many moles of oxygen are required

As shown in the equation the molar ratio of H2 to H20 is 1:1, therefore if 8 moles of H2 are used, 8 moles of H2O are produced. However the molar ratio of H2 to O2 is 2:1 therefore the number of moles of O2 required is 8/2 = 4.

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Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.