Question

An unknown compound contains only carbon, hydrogen, and oxygen (cxhyoz). combustion of 3.50 g of this compound produced 5.13 g of carbon dioxide and 2.10 g of water.how many moles of hydrogen, h, were in the original sample?

Answer 1

The formula for determining the number of moles is:

$number of moles = \frac{mass}{molecular weight}$

Mass of compound = $3.5 g$

Mass of carbon dioxide produced = $5.13 g$

Mass of water produced = $2.10 g$

Molecular weight of water, $H_2O = 18 g/mol$

Substituting the values in above equation:

$number of moles = \frac{2.10 g}{18 g/mol}= 0.11667 mole$

Since, 1 mole of water contains 2 moles of hydrogen therefore, number of moles of hydrogen = $0.11667 mole\times 2 = 0.23334 mole$