Question

Mercury(II) oxide (HgO) decomposes to form mercury (Hg) and oxygen (O2). The balanced chemical equation is shown below. 2HgO mc020-1.jpg 2Hg + O2 The molar mass of HgO is 216.59 g/mol. The molar mass of O2 is 32.00 g/mol. How many moles of HgO are needed to produce 250.0 g of O2?

Answer 1

Answer:

moles of HgO needed to produce 250.0 g of O2 = 15.63 moles

Explanation:

The chemical reaction is:

$2HgO\rightarrow 2Hg + O2$

Amount of O2 produced = 250.0 g

Molar mass of HgO = 216.59 g/mol

Molar mass of O2 = 32.00 g/mol

Moles of O2 produced = $\frac{Mass\ of\ O2}{Molar\ Mass} = \frac{250.0g}{32 g/mol } = 7.813 moles$

Based on the reaction stoichiometry:

2 moles of HgO produces 1 mole of O2

Therefore, moles of HgO needed to produce 7.813 moles of O2 is:

= $\frac{7.813\ O2 * 2\ HgO}{1\ O2} = 15.63 moles$

Answer 2

2HgO = 2Hg + O₂

n(HgO)=2n(O₂)=2m(O₂)/M(O₂)

m(HgO)=n(HgO)M(HgO)=2m(O₂)M(HgO)/M(O₂)

m(HgO)=2*250.0*216.59/32.00 = 3384.219 g ≈ 3 kg 384 g