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Combustion Analysis Calculations 5. GRAS List for Food Additives The alcohol ger

ID: 1037211 • Letter: C

Question

Combustion Analysis Calculations 5. GRAS List for Food Additives The alcohol geraniol is on the U.S. Food and Drug Administration's GRAS (generally recognized as safe) list and can be used in foods and personal care products. By itself, geraniol has a roselike odor, but it is frequently blended with other scents to produce the fruity fragrances of some personal care products Complete combustion of 175 mg of geraniol produces 499 mg CO2 and 184 mg H20. What is the empirical formula of geraniol? 6. Combustion of 135.0 mg of a hydrocarbon produces 440.0 mg CO and 135.0 mg HgO. The molar mass of the hydrocarbon is 270 g/mol. What are the empirical and molecular formulas of this compound? 7.The combustion of 40.5 mg of a compound extracted from the bark of the sassafras tree and known to contain C, H, and O produces 110.0 mg COp and 22.5 mg H2O. The molar mass of the compound is 162 g/mol. What are its empirical and molecular formulas?

Explanation / Answer

Given

mass of geraniol = 175 mg

molar mass of geraniol = 154.25 mg/mmol

No. of moles of gerniol = 175 mg / 154.25 mg/mmol = 1.1345 mmol

mass of CO2 = 499 mg

molar mass of CO2 = 44 mg/mmol

No. of moles of CO2 = 499 mg / 44 mg/mmol = 11.34 mmol

mass of H2O = 184 mg

molar mass of H2O = 18 mg/mmol

no. of moles of H2O = 184 mg / 18 mg/mmol = 10.22 mmol

CxHy + O2 ---> CO2 + H2O

one mole of CO2 will contain 1 mole of C

x * no. of moles of geraniol = 1 * no. of moles of CO2

x * 1.134 = 1 * 11.34

x = 10

one mole of H2O will contain 2 moles of H

y * no. of moles of geraniol = 2 * no. of moles of H2O

y * 1.134 = 2 * 10.22

y = 18

so emprical formula is C10H18O .

O is because its an alcohol

so answer is C10H18O .