What is the molecular formula for the compound that is made up of 30.45 g N and 69.55 g O, and has a formula mass of 92.02 amu?

1 Answer
Apr 14, 2018

Answer:

#"N"_2"O"_4#

Explanation:

Moles of nitrogen

#"n"_"N" = "30.45 g"/"14 g/mol" = "2.175 mol"#

Moles of oxygen

#"n"_"O" = "69.55 g"/"16 g/mol" = "4.347 mol"#

Ratio of moles of nitrogen and oxygen

#"n"_"N"/"n"_"O" = "2.175 mol"/"4.347 mol" ≈ 1/2#

∴ Emperical formula #"= NO"_2#

#"Molecular formula mass"/"Emperical formula mass" = "92.02 amu"/"46.0 amu" ≈ 2#

∴ Molecular formula #= 2 × "NO"_2 = color(Green)("N"_2"O"_4)#