When 83.3 grams of phosphorus pentachloride react with an excess of water, as shown in the unbalanced chemical equation below, how many moles of hydrochloric acid will be produced?

PCl5 + H2O yields H3PO4 + HCl

0.4 moles
1.0 moles
1.6 moles
2.0 moles

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unicorngirl15 unicorngirl15 · Answer 1 · 2018-04-18T08:41:44+02:00

2.0 moles. (83.3g / 208 [grams/moles] *5 [from balancing] = around 2

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lcoley8 lcoley8 · Answer 2 · 2020-03-07T03:41:36+01:00

Answer:

The answer is 2 moles of HCl

Explanation:

To solve we have to adjust the equation:

PCl5 + 4H2O = 5HCl + H3PO4

we calculate the molecular weights of the compounds using the periodic table:

P = 30.97 g/mol

Cl = 5x35.45 = 177.25 g/mol

H = 1 g/mol

PCl5 = 30.97+177.25 = 208.22 g/mol

HCl =1+35.45 = 36.45 g/mol

we use a rule of three to calculate the mass of hydrochloric acid that forms when the 83.3 phosphorus pentachloride reacts:

208.22 g PCl5-----------------182.25 g HCl

83.3 g PCl5------------------------X g HCl

Clearing the X, we have:

X g HCl = (83.3x182.25)/208.22 = 72.91 g HCl

we calculate the moles of hydrochloric acid:

Moles of HCl = 72.91/36.45 = 2 moles of HCl