Ch.6 - Thermochemistry WorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: It is often argued that natural gas (CH4) is preferred to petroleum (which we will approximate as isooctane, C8H18) in generating energy in that it produces less CO 2. The balanced  combustion reactions for CH4 and C8H18  are given below. CH4(g)  +  2O2(g)  →  CO2(g)  +   2H2O(g) 2C8H18(g)  +  25O2(g)  →  16CO2(g)  +   18H2O(g) Using the following heats of formation, calculate Joules of energy generated per mole of CO2 produced for each combustion. Is methane better than petroleum in lowering CO2 production (in other words, does it produce more CO2 per joules of energy)? H2O(g)       ΔH°f = -241.83 kJ/mol                CO2(g)       ΔH°f = -395.51 kJ/mol CH4(g)       ΔH°f = -74.1 kJ/mol                    C8H18(g)   ΔH°f = -224.1 kJ/mol  

Problem

It is often argued that natural gas (CH4) is preferred to petroleum (which we will approximate as isooctane, C8H18) in generating energy in that it produces less CO 2. The balanced  combustion reactions for CH4 and C8H18  are given below.

CH4(g)  +  2O2(g)    CO2(g)  +   2H2O(g)

2C8H18(g)  +  25O2(g)    16CO2(g)  +   18H2O(g)

Using the following heats of formation, calculate Joules of energy generated per mole of CO2 produced for each combustion. Is methane better than petroleum in lowering CO2 production (in other words, does it produce more CO2 per joules of energy)?

H2O(g)       ΔH°f = -241.83 kJ/mol               

CO2(g)       ΔH°f = -395.51 kJ/mol

CH4(g)       ΔH°= -74.1 kJ/mol                   

C8H18(g)   ΔH°f = -224.1 kJ/mol