CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
A 0.800 g sample of a compound containing carbon, hydrogen, nitrogen, and oxygen is subjected to the following analyses.
• Complete combustion in excess O₂ produces 1.19 g of CO₂(g) and 0.566 g of H₂O(g).
• Separate Dumas analysis of the same sample yields 0.126 g of N₂(g).
Assume all carbon in the compound is converted to CO₂, all hydrogen to H₂O, and all nitrogen to N₂. Any remaining mass is attributed to oxygen.
(a) Calculate the moles of carbon, hydrogen, and nitrogen atoms present in the sample.
(b) Determine the mass and number of moles of oxygen atoms present in the original compound.
(c) Derive the empirical formula of the compound, presenting a clear progression from the elemental mole data to the simplest whole-number ratio.