
Concept explainers
(a)
Interpretation:
The chemical equations for the combustion of propane and ethyne have to be written.
Concept Introduction:
A hydrocarbon undergoes complete combustion to produce carbon dioxide and water. This is chemical property of all hydrocarbons.
Complete combustion occurs if enough oxygen is present.
Incomplete combustion occurs, if there is not enough oxygen present. Incomplete combustion results in the formation of toxic gases.
(a)

Answer to Problem 11.47E
The chemical equation for complete combustion reaction of propane is,
C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)
The chemical equation for complete combustion reaction of ethyne (Acetylene) is,
2C2H2(g)+5O2(g)→4CO2(g)+2H2O(g)
Explanation of Solution
Combustion reaction of Propane:
Propane undergoes complete combustion reaction to form carbon dioxide and water.
The chemical equation for complete combustion reaction of propane is,
C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)
The incomplete combustion reaction of propane results in the formation of carbon, carbon monoxide, carbon dioxide and water. The chemical equation for incomplete combustion reaction of propane is,
2C3H8(g)+7O2(g)→2C(s)+2CO(g)+2CO2(g)+8H2O(g)
Combustion reaction of Acetylene:
Acetylene (or) ethyne undergoes complete combustion reaction to form carbon dioxide and water vapor as their products. The chemical equation for complete combustion reaction of acetylene is,
2C2H2(g)+5O2(g)→4CO2(g)+2H2O(g)
(b)
Interpretation:
The enthalpy of combustion for each fuel per gram and per mole has to be calculated.
Concept Introduction:
Hess Law:
The total enthalpy change during the complete course of a
ΔHoreaction=ΔHof(products)-ΔHof(reactants)
(b)

Explanation of Solution
Combustion reaction of Propane:
Propane undergoes complete combustion reaction to form carbon dioxide and water.
The chemical equation for complete combustion reaction of propane is,
C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)
Enthalpy of combustion of propane:
Heat of formation of propane=-104 kJ/mole
Heat of formation of carbon dioxide gas=-394 kJ/mole
Heat of formation of water=-241.8 kJ/mole
The enthalpy of combustion of propane is,
ΔHocombustion=ΔHof(products)-ΔHof(reactants)ΔHocombustion=((3)(-394kJ/mole)+(4)(-241.8kJ/mole))-((1)(-104kJ/mole)+(5)(0))ΔHocombustion=-1182kJ/mole+(-967.2kJ/mole)-(-104kJ/mole)ΔHocombustion=-2045.2kJ/mole
The enthalpy of combustion of propane is -2045.2 kJ/mole.
The enthalpy of combustion of propane is -2045.2 kJ per 44 grams of propane.
Combustion reaction of Acetylene:
Acetylene (or) ethyne undergoes complete combustion reaction to form carbon dioxide and water vapor as their products. The chemical equation for complete combustion reaction of acetylene is,
2C2H2(g)+5O2(g)→4CO2(g)+2H2O(g)
Enthalpy of combustion of acetylene:
Heat of formation of acetylene=226.7 kJ/mole
Heat of formation of carbon dioxide gas=-394 kJ/mole
Heat of formation of water=-241.8 kJ/mole
The enthalpy of combustion of acetylene is,
ΔHocombustion=ΔHof(products)-ΔHof(reactants)ΔHocombustion=((4)(-394kJ/mole)+(2)(-241.8kJ/mole))-((2)(226.7 kJ/mole)+(5)(0))ΔHocombustion=-1576 kJ/mole+(-483.6 kJ/mole)-(453.4 kJ/mole)ΔHocombustion=-2513 kJ/mole
The enthalpy of combustion of acetylene is -2513 kJ/mole.
The enthalpy of combustion of acetylene is -2513 kJ per 26.04 grams of acetylene.
(c)
Interpretation:
The reason why propane torches are not used for wielding has to be calculated.
(c)

Explanation of Solution
Propane undergoes complete combustion reaction to form carbon dioxide and water.
The chemical equation for complete combustion reaction of propane is,
C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)
The enthalpy of combustion of propane is -2045.2 kJ/mole.
Acetylene (or) ethyne undergoes complete combustion reaction to form carbon dioxide and water vapor as their products. The chemical equation for complete combustion reaction of acetylene is,
2C2H2(g)+5O2(g)→4CO2(g)+2H2O(g)
The enthalpy of combustion of acetylene is -2513 kJ/mole.
The enthalpy of combustion of propane is higher than the enthalpy of combustion of acetylene, and hence it cannot be used for wielding purposes. It also produces a lower flame temperature and the pre-heat time is more. Propane cannot be used for gas wielding because it does not have a reducing zone.
Want to see more full solutions like this?
Chapter 11 Solutions
Chemical Principles: The Quest for Insight
- 2.0arrow_forwardWrite the electron configuration of an atom of the element highlighted in this outline of the Periodic Table: 1 23 4 5 6 7 He Ne Ar Kr Xe Rn Hint: you do not need to know the name or symbol of the highlighted element! ☐arrow_forwardCompare these chromatograms of three anti-psychotic drugs done by HPLC and SFC. Why is there the difference in separation time for SFC versus HPLC? Hint, use the Van Deemter plot as a guide in answering this question. Why, fundamentally, would you expect a faster separation for SFC than HPLC, in general?arrow_forward
- A certain inorganic cation has an electrophoretic mobility of 5.27 x 10-4 cm2s-1V-1. The same ion has a diffusion coefficient of 9.5 x 10-6cm2s-1. If this ion is separated from cations by CZE with a 75cm capillary, what is the expected plate count, N, at an applied voltage of 15.0kV? Under these separation conditions, the electroosmotic flow rate was 0.85mm s-1 toward the cathode. If the detector was 50.0cm from the injection end of the capillary, how long would it take in minutes for the analyte cation to reach the detector after the field was applied?arrow_forward2.arrow_forwardPlease solve for the following Electrochemistry that occursarrow_forward
- Commercial bleach contains either chlorine or oxygen as an active ingredient. A commercial oxygenated bleach is much safer to handle and less likely to ruin your clothes. It is possible to determine the amount of active ingredient in an oxygenated bleach product by performing a redox titration. The balance reaction for such a titration is: 6H+ +5H2O2 +2MnO4- à 5O2 + 2Mn2+ + 8H2O If you performed the following procedure: “First, dilute the Seventh Generation Non-Chlorine Bleach by pipetting 10 mL of bleach in a 100 mL volumetric flask and filling the flask to the mark with distilled water. Next, pipet 10 mL of the diluted bleach solution into a 250 mL Erlenmeyer flask and add 20 mL of 1.0 M H2SO4 to the flask. This solution should be titrated with 0.0100 M KMnO4 solution.” It took 18.47mL of the KMnO4 to reach the endpoint on average. What was the concentration of H2O2 in the original bleach solution in weight % assuming the density of bleach is 1g/mL?arrow_forward10.arrow_forwardProper care of pH electrodes: Why can you not store a pH electrode in distilled water? What must you instead store it in? Why?arrow_forward
- Write the electron configuration of an atom of the element highlighted in this outline of the Periodic Table: 1 23 4 569 7 He Ne Ar Kr Xe Rn Hint: you do not need to know the name or symbol of the highlighted element! §arrow_forwardIdentify the amino acids by name. Illustrate a titration curve for this tetrapeptide indicating the pKa's for each ionizable groups and identify the pI for this tetrapeptide. please helparrow_forward↓ ina xSign x Sign X labs X Intro X Cop Xa chat X My Cx Grac X Laur x Laur xash learning.com/ihub/assessment/f188d950-dd73-11e0-9572-0800200c9a66/d591b3f2-d5f7-4983-843c-0d00c1c0340b/f2b47861-07c4-4d1b-a1ee-e7db2 +949 pts /3400 K Question 16 of 34 > © Macmillan Learning Draw the major E2 reaction product formed when cis-1-chloro-2-ethylcyclohexane (shown) reacts with hydroxide ion in DMSO. H CH2CH3 H H HO- H H H Cl DMSO H H C Select Draw Templates More C H 0 2 Erasearrow_forward
- Chemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage LearningOrganic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning
- Introductory Chemistry: An Active Learning Approa...ChemistryISBN:9781305079250Author:Mark S. Cracolice, Ed PetersPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning





