STOICHIOMETRY REACTION

Question

What volume of oxygen gas is produced when 29.1 g of mercury(II) oxide reacts completely according to the following reaction at 25 °C and 1 atm?

mercury(II) oxide (s) mercury (l) + oxygen(g)

Answer 1

Write the correctly balanced equation:

2HgO(s) ==> 2Hg(l) + O₂(g)

Calculate moles of HgO that are present: 29.1 g HgO x 1 mol HgO/216.59 g = 0.1344 moles HgO

Use the balanced equation to find moles of O2: 0.1344 mol HgO x 1 mol O2/2 mol HgO = 0.06718 mol O2

Use ideal gas law to find volume of O2: PV = nRT and V = nRT/P

V = (0.06718 mol)(0.0821 L-atm/K-mol)(298K)/1 atm

V = 1.64 L (to 3 significant figures)