Menthol, a flavoring agent obtained from peppermint oil,...

Menthol, a flavoring agent obtained from peppermint oil, contains carbon, hydrogen, and oxygen. On combustion analysis, $1.00 \mathrm{~g}$ of menthol yields $1.161 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{O}$ and $2.818 \mathrm{~g}$ of $\mathrm{CO}_{2}$. What is the empirical formula of menthol? Check your answer with the structural formula provided.

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Key Concepts

Stoichiometry Calculations

Stoichiometry calculations involve using established mole ratios from balanced chemical equations to interconvert between masses, moles, and numbers of molecules. This process is essential for analyzing reaction outcomes and deriving the elemental composition from experimental data.

Mole Concept

The mole concept is a cornerstone of stoichiometry, linking the mass of substances to the number of entities (such as atoms or molecules). It allows chemists to convert measured masses into moles, facilitating comparisons and calculations required for determining empirical formulas.

Combustion Analysis

Combustion analysis is an experimental technique used to determine the elemental composition of an organic compound by completely burning it in oxygen. The amounts of CO2 and H2O produced are measured, and these values are used to deduce the number of moles of carbon and hydrogen present in the original compound.

Empirical Formula Determination

Empirical formula determination involves calculating the simplest whole-number ratio of the constituent elements in a compound based on experimental data. The process typically uses the masses or moles of elements obtained from techniques like combustion analysis to reveal the compound's basic composition.

Transcript

00:01 A combustion analysis problem, menthol, which is a flavoring obtained for peppermine oil, contains carbon, oxygen, and hydrogen.

00:10 We have a 1 .00 gram sample.

00:17 In that sample, on combustion analysis, we get 1 .161 grams of water, and we get 2 .818 grams of co2.

00:34 And we're asked to find the empirical formula.

00:40 Check your answer with the structural formula provided.

00:44 And where is there a structural formula? i do not see a structural formula.

00:55 I'm looking everywhere for a structural formula.

01:07 Oh, there it is.

01:08 Well, i'm not going to copy that on there.

01:11 Okay, so this is a pretty easy problem to solve.

01:15 We're going to find moles of c.

01:19 We're going to find moles of each of these.

01:22 So to find moles of my water, it's 18 .02 grams per mole.

01:31 My co2 is 44 .01.

01:34 Grams per mole equals equals.

01:40 And then i'm going to figure out moles of, for this one i'm going to go, one mole of co2 has one mole of carbon, and one mole of h2 has two moles.

02:00 Of hydrogen.

02:01 There we go.

02:04 So now for my carbon i can get zero point around later if i need to.

02:13 That's how many moles of c i have.

02:16 And i have the 0 .1, 2885 moles of h.

02:25 Now the only thing i don't have so far is oxygen...

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