Answer:
There will be produced 3.5 moles of oxygen (O2)
Step-by-step explanation:
Step 1: Data given
Number of moles Mercury (II) oxide (HgO) = 7 moles
Step 2: The balanced equation
2HgO → O2 + 2Hg
Step 3: Calculate number of moles of O2
For 2 moles of Mercury (II) oxide (HgO) we produce 1 mol of O2 and 2 moles of Hg
For 7 moles of Mercury (II) oxide (HgO) we'll have 7/2 = 3.5 moles of O2
There will be produced 3.5 moles of oxygen (O2)