Question

Pure oxygen gas was first prepared by heating mercury(II) oxide, HgO: 10.72 2 HgO(s)-? 2Hig(I) + 02(g) What volume in liters of oxygen at STP is released by heating 10.57 g of HgO? 10.73 How many grams of HgO would you need to heat if you wanted to prepare 0.0155 mol of O2 according to the equation in Problem 10.72?

Answer 1

2Hgo (s) rightarrow 2Hg(l) + O_2 (g) moles of Hgo = wt/mu.wt = 10.57 g/216.6 g/mol = 0.0488 moles 2 moles of Hgo (s) gives 1 mole of O_2 0.0488 moles of Hgo (s) gives x moles of O_2 x = 0.0488 times 1/2 = 0.0244 moles of o_2 at STP 1moles of O_2 gives 22.4 lit of o_2 0.0244 moles o_2 gives x lit x = 0.0244 times 22.4/1 = 0.546 lit 0.546 lit of 'o_2' produced Answer 73 1 mole of o_2 obtained from 2 moles of Hgo 1 mole of o_2 obtained from 2 times 216.6 g of Hgo from 0.0155 mol o_2 obtained x g of Hgo x = 0.0155 mol times 2 times 215.6 g/1 mol x = 6.71 g of Hgo Answer