Practice: Valproic acid, used to treat seizures, is composed of carbon, hydrogen and oxygen. A 0.165 g sample is combusted to produce 0.166 grams of water and 0.403 grams of carbon dioxide. If the molar mass is 144 g/mol, what is the molecular formula?
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| Empirical Formula | 14 mins | 0 completed | Learn Summary |
| Molecular Formula | 20 mins | 0 completed | Learn |
| Combustion Analysis | 39 mins | 0 completed | Learn |
| Combustion Apparatus | 16 mins | 0 completed | Learn |
| Polyatomic Ions | 25 mins | 0 completed | Learn Summary |
| Naming Ionic Compounds | 11 mins | 0 completed | Learn |
| Writing Ionic Compounds | 7 mins | 0 completed | Learn |
| Naming Ionic Hydrates | 6 mins | 0 completed | Learn |
| Naming Acids | 18 mins | 0 completed | Learn |
| Naming Molecular Compounds | 6 mins | 0 completed | Learn |
| Balancing Chemical Equations | 17 mins | 0 completed | Learn |
| Stoichiometry | 23 mins | 0 completed | Learn Summary |
| Limiting Reagent | 21 mins | 0 completed | Learn Summary |
| Percent Yield | 20 mins | 0 completed | Learn Summary |
| Mass Percent | 4 mins | 0 completed | Learn Summary |
| Functional Groups in Chemistry | 11 mins | 0 completed | Learn |
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| Ionic and Covalent Compounds |
| Metal Alloys |
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| Theoretical Yield (IGNORE) |
| Balancing Chemical Equations Worksheet (IGNORE) |
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Under Combustion Analysis, the empirical formula of a compound is determined through a combustion reaction.
Combustion Analysis
Example #1: A 0.2500 g sample contains carbon, hydrogen and oxygen and undergoes complete combustion to produce 0.3664 g of CO2 and 0.1500 g of H2O. What is the empirical formula of the compound?
Practice: When hydrocarbons are burned in a limited amount of air, both CO and CO2 form. When 0.460 g of a hydrocarbon was burned in air, 0.477 g of CO, 0.749 g CO2, and 0.460 g of H2O were formed. What is the empirical formula of the compound?
Example #2: A solvating agent (MW = 147.0 g/mol) that contains C, H, and Cl is used for spectroscopic processes. Determine its molecular formula when a 0.250 g sample creates 0.451 g CO2 and 0.0617 g of H2O upon combustion.
Practice: If a compound made of calcium, carbon, nitrogen undergoes combustion in oxygen to create 2.389 g CaO, 1.876 g CO2, and 3.921 g NO2, determine its empirical formula.
Practice: The combustion of 4.16 grams of a compound which contains only C,H,O and F yields 7.7 g CO2 and 2.52 g H2O. Another sample of the compound with a mass of 3.63 g is found to contain 0.58 g F. What is the empirical formula of the compound?
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Videos in Combustion Analysis
Concept #1: Combustion Analysis
Example #1: Combustion Analysis Example 1
Practice #1: Combustion Analysis Practice 1
Practice #2: Combustion Analysis Practice 2
Concept #2: Combustion Analysis
Example #2: Combustion Analysis Example 2
Practice #3: Combustion Analysis Practice 3
Practice #4: Combustion Analysis Practice 4
Additional Problems
Thiophene contains only the elements carbon, hydrogen and sulfur. A sample weighing 7.96 g was burned in oxygen to give 16.65 g CO2 and 3.40 g of H2O. What is the empirical formula of thiophene?
a) C2H2S
b) C4H4S
c) C2H4S3
d) C2H4S
e) C4H4S3
The complete combustion of 0.285 g of a pure hydrocarbon yielded 0.878 g CO 2 and 0.405 g H2O. What is the mass % C in this hydrocarbon?
A) 24.0%
B) 72.7%
C) 27.3%
D) 32.4%
E) 84.1%
Para-cresol is used as a disinfectant. A 0.3654 g sample of this compound that contains only C, H, and O, gave 1.0420 g CO2 and 0.2437 g H2O in a combustion analysis. Its molecular mass is 108.1g/mol. What is its molecular formula? a. C7H8Ob. C6H7Oc. C7H7O2d. C6H7O2e. C7H8O2
What are the products of the combustion of octane (C 8H18)A. O2 and C4H9B. H2O and C4H9C. CO2 and H2OD. O2 and CO2
A hydrocarbon with general formula CxHy was burned completely in air, yielding 0.18 g of water and 0.44 g of carbon dioxide. Which formula could give such data?A. C2H2B. C2H4C. C2H6D. C6H6
Combustion analysis of 63.8 mg of a C, H and O containing compound produced 145.0 mg of CO2 and 59.38 mg of H2O. What is the empirical formula for the compound?A) C5H2OB) CHOC) C3H6OD) C3H7OE) C6HO3
A 2.000 g sample of an unknown metal, M, was completely burned in excess O 2 to yield 0.02224 mol of the metal oxide, M2O3. What is the metal?a) Alb) Scc) Cad) Y
Combustion analysis of naphthalene, a hydrocarbon used in mothballs, produced 8.80 g CO2 and 1.44 g H2O. Calculate the empirical formula for naphthalene.
Tartaric acid is the white, powdery substance that coats tart candies such as Sour Patch Kids. Combustion analysis of a 12.01 g sample of tartaric acid-which contains only carbon, hydrogen, and oxygen-produced 14.08 g CO2 and 4.32 g H2O. Determine the empirical formula for tartaric acid.
Estrone, which contains only carbon, hydrogen, and oxygen, is a female sexual hormone that occurs in the urine of pregnant women. Combustion analysis of a 1.893 g sample of estrone produces 5.545 g of CO2 and 1.388 g H2O. The molar mass of estrone is 270.36 g/mol. Find the molecular formula for estrone.
Researchers obtained the following data from experiments to find the molecular formula of benzocaine, a local anesthetic, which contains only carbon, hydrogen, nitrogen, and oxygen. Complete combustion of a 3.54 g sample of benzocaine with excess O2 formed 8.49 g of CO2 and 2.14 g H2O. Another sample of mass 2.35 g was found to contain 0.199 g of N. The molar mass of benzocaine was found to be 165 g/mol. Find the molar formula benzocaine .
There are two binary compounds of mercury and oxygen. Heating either of them results in the decomposition of the compound, with oxygen gas escaping into the atmosphere while leaving a residue of pure mercury. Heating 0.6498 g of one of the compounds leaves a residue of 0.6018 g. Heating 0.4172 g of the other compound results in a mass loss of 0.016 g. Determine the empirical formula of each compound.
A compound contains only carbon, hydrogen, and oxygen. Combustion of 10.68 mg of the compound yields 16.01 mg CO2 and 4.37 mg H2O. The molar mass of the compound is 176.1 g/mol. What are the empirical and molecular formulas of the compound?
A 4.05 g sample of a compound containing only C, H, and O was burned completely. The only combustion products were 10.942 g CO2 and 4.476 g H2O. What is the empirical formula of the compound?A) C7H7OB) C7H14O7C) CH2OD) C7H14OE) C6H12O
Combustion analysis of an unknown compound containing only carbon and hydrogen produced 4.554 g of CO2 and 2.322 g of H2O. What is the empirical formula of the compound?A) C4H10B) CH2 C) C2H5D) C5H2
2.404 g of a compound were burned in oxygen and found to produce only 3.520 g CO2 (g), 2.564 g SO2 (g) and 1.440 g H2O (l). Determine the empirical formula of the compound.A) C2SH4B) C2SH2C) CSHD) C4SH2 E) C2S2H4
Combustion analysis of a 12.01 g sample of tartaric acid, which contains only carbon, hydrogen, and oxygen, produced 14.08 g CO2 and 4.32 g H2O.a) What is the empirical formula of tartaric acid? b) If 0.250 moles of the compound weighs 37.52 g, what is the molecular formula of the compound?
The combustion of 4.16 grams of a compound which contains only C,H,O and F yields 7.7 g CO2 and 2.52 g H2O. Another sample of the compound with a mass of 3.63 g is found to contain 0.58 g F. What is the empirical formula of the compound? A. C3H8O2FB. C4H10OFC. C4H8OFD. C5H8O2F
A strip of pure copper metal weighing 3.178 g is heated in the presence of oxygen gas. In the process, all of the copper reacts with oxygen to form 3.978 g of a black copper oxide. What is the empirical formula for this copper oxide?Given that the molar mass of the compound is about 80 g, name this compound.
On combustion analysis, a 0.450 g sample of a chemical compound gives 0.418 g of water and 1.023 g of carbon dioxide. Assuming that the empirical formula of the compound is CxHyOz, find the values of x, y and z.
Combustion analysis of 2.400 g of an unknown compound containing carbon, hydrogen, and oxygen produced 4.171 g of CO2 and 2.268 g of H2O. What is the empirical formula of the compound?A) C2H5O2B) C2H5OC) C2H10O3 D) C3H8O2
Isoeugenol is the compound which gives the characteristic odor to nutmeg and contains carbon, hydrogen, and oxygen. If a 0.500 g sample of isoeugenol is combusted it gives 1.341 g of CO2 and 0.329 g of H2O. Isoeugenol has a molecular weight of 164 g/mol. What is the molecular formula of isoeugenol?A) C8H4O4B) C10H12O2 C) C2HOD) C5H6O
What are the products of the combustion of octane (C 8H18)?A. O2 and C4H9B. H2O and C4H9C. CO2 and H2OD. O2 and CO2
Determine the empirical formula for a hydrocarbon if the complete combustion of a sample produces 5.28 g of CO2 and 1.62 g of H2O.