A quantity of 20.00 g of mercury(II) oxide is decomposed by heating. Calculate the mass of oxygen gas that could be produced. 2HgO(s)  2Hg(l) + O2(g)

Answer 1

2HgO(s) ==> 2Hg(l) + O₂(g) ... balanced equation

molar mass HgO = 216.6 g / mol

molar mass O₂ = 32 g / mol

Use stoichiometry (mol ratio) of the balanced equation along with dimensional analysis to calculate:

20.00 g HgO x 1 mol HgO / 216.6 g x 1 mol O₂ / 2 mol HgO x 32 g O₂ / mol = 1.477 g O₂ (4 sig.figs.)