Question

How many total moles of acid are formed when starting with 4.5 g of PCl5 and excess H2O? PCl5 + 4H2O --> 5HCl + H3PO4

Answer 1

Answer: 0.1296 moles

Step-by-step explanation:

Assuming we have excess water, we only need to focus on the moles of
`PCl_(5)`.
`PCl_(5)` has a molar mass of 208.24 g/mol. The number of moles of
`PCl_(5)` we have is
`(4.5)/(208.24)` or 0.0216 moles.

The two acids are HCl and H3PO4. First lets focus on the number of moles of HCl formed.

The ratio of the number of moles of HCl formed and the number of moles of
`PCl_(5)` used is:
`(moles PCl5)/(moles HCl) = (1)/(5)`, plugging in, we get that moles of HCl = 0.108.

The ratio of the number of moles of H3PO4 formed and the number of moles of
`PCl_(5)` used is:
`(moles PCl5)/(moles H3PO4) = (1)/(1)`, plugging in, we get that moles of H3PO4 = 0.0216.

The total number of moles of acid formed is 0.0216+0.108 = 0.1296.