Problem: Combustion analysis of toluene, a common organic solvent, gives 6.45 mg of CO2 and 1.51 mg of H2O. If the compound contains only carbon and hydrogen, what is its empirical formula?

FREE Expert Solution

Recall that in combustion analysisa compound reacts with excess O2 to form products


mole-to-mole comparison:

  • 1 mmole of C in 1 mmole of CO(molar mass = 44.01 g/mol or mg/mmol)
  • 2 mmoles of H in 1 mmole of H2(molar mass = 18.02 mg/mmol)


mmoles of C=6.45 mg CO2×1 mmol CO244.01 mg CO2×1 mmol C1 mmol CO20.147 mmol C


mmoles of H=1.51 mg H×1 mmol H2O18.02 mg H2O×2 mmol H1 mmol H2O

0.168 mmol H


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Problem Details

Combustion analysis of toluene, a common organic solvent, gives 6.45 mg of CO2 and 1.51 mg of H2O. If the compound contains only carbon and hydrogen, what is its empirical formula?

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