Question

Mercury(II) oxide (HgO) decomposes to form mercury (Hg) and oxygen (O2). The balanced chemical equation is shown below.

2HgO 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?
3.906
7.813
15.63
73.87

Answer 1

The answer to the question is C. 15.63

Answer 2

Answer:

15.63 moles of HgO are needed to produce 250.0 g of $O_{2}$

Explanation:

According to given balanced equation, 1 mole of $O_{2}$ is produced from 2 moles of HgO.

Number of moles $=\frac{mass}{molar mass}$

So 250 g of $O_{2}$ $=\frac{250}{32}moles O_{2}$

So moles of HgO needed $=2\times \frac{250}{32}moles HgO$

                                                   $=15.63 moles HgO$