Answer:
7.8 moles are needed.
Explanation:
Given data:
Mass of oxygen produced = 125 g
Number of moles of mercury oxide needed = ?
Solution:
Chemical equation;
2HgO → 2Hg + O₂
Number of moles of oxygen:
Number of moles = mass/ molar mass
Number of moles = 125 g/ 32 g/mol
Number of moles = 3.9 mol
Now we will compare the moles of oxygen with mercury oxide.
O₂ : HgO
1 : 2
3.9 : 2×3.9 = 7.8 mol