empirical formula nicotine

Nicotine, a component of tobacco, from C, H and N. .. together?

A 7.350-mg sample of nicotine was burned, producing CO2 and 5.716 mg 19.939 mg H2O. What is the chemical formula for nicotine?

Moles CO2 = 0.019939 g / 44.0098 g / mol = 0.0004531 mol C = mass C = 0.0004531 x 12.011 g / mol = 0.005442 g Moles water = 0.005716 g / 18.02 g / mol = 0.0003172 Moles H = 2 x 0.0003172 = 0.0006344 Mass H = 1.008 g / mol x 0.0006344 = 0.0006395 mol grams N = 0.007350 — 0.005442 – 0.0006395 = 0.001269 N = 0.001269 Moles g / 14.0067 g / mol = 0.00009056 we divide by the smallest number 0.0004531 / 0.00009056 = 5 => C 0.0006344 / 7 = 0.00009056 => H 0.00009056 / 0.00009056 = 1 => NC 5 H7 N