What is the empirical formula of a phosphoric acid that contains 0.3086 g of hydrogen, 3.161 g of phosphorus, and 6.531 g of oxygen?

1 Answer
Manish Bhardwaj
Apr 29, 2016

#H_2# # P_4# #O_1#

Explanation:

In order to calculate the Empirical formula , we will assume that we have started with 10 g of the compound. On decomposition , we obtained 0.3086 g of Hydrogen , 3.161 g of Phosphorus, and 6.531 g of Oxygen.

*Step 1* Calculating the number of moles of different elements

#n_##H#= mass of H/ molar mass of H

#n_##H #= 0.3086 g / 1 g #mol^(-1)#

#n_##H#= 0.3086 mol

#n_#P## = mass of P/ molar mass of P

#n_#P#= 3.161 g / 31 g #mol^(-1)#

#n_##P#= 1.02 mole

#n_##O# = mass of O / molar mass of O

#n_##O#= 6.531 g / 32 g #mol^(-1)#

#n_##O#= 0.2 mol

Calculating the Simple Ratio of the moles

H= 0.3806/ 0.2 =4 , P = 1.02 / 0.2 =5 , O= 0.2/0.2 =1

#H_2# # P_4# #O_1#

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