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InterviewSolution
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1.0 g of magnesium is burnt with 0.56 g O2 in aclosed vessel. Which reactant is left in excessand how much? (At wt Mg 24: 0-16)[AIPMT-2014)(1) Mg. 0.16 g(3) Mg. 0.44 g(2) O2 0.16 g(4) 02, 0.28 g |
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Answer» The equation is as follows:2Mg + O2 ------> 2MgO(s) (g) (s)Therefore 2 moles of Mg require 1 mole of O2 to produce 2 moles of MgO.Calculate actual moles.moles= mass/ molar massMg= 1/24 = 0.041667O2= 0.56/32 = 0.0175MgO=Mole ratio of Mg: O2 = 2:1find mass of Mg that reacts:that means 2 mole of Mg reacts with 1 moles of O2If 1 = 2Then 0.0175 = 0.0175 x 2=0.035 moles of magnesiummass of magnesium that reacts:mass= moles x molar mass= 24 x 0.0350.84 gThat means that of the 1 gram of magnesium that reacts only 0.84 grams is usedTherefore magnesium is in excess and by 0.16 |
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