Ch.1 - Intro to General ChemistryWorksheetSee 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: Gasoline is a mixture of hydrocarbons, but the heat released when it burns is close to that of octane, C8H18(l) (ΔH°f = −250.1 kJ/mol). Research is underway to use H 2 from the electrolysis of water in fuel cells to power cars instead of gasoline.(a) Calculate ΔH° when 1.00 gal of gasoline (d = 0.7028 g/mL) burns to produce carbon dioxide gas and water vapor.(b) How many liters of H2 at 25°C and 1.00 atm must burn to produce this quantity of energy?(c) How long would it take to produce this amount of H 2 by electrolysis with a current of 1.00 × 10 3 A at 6.00 V?(d) How much power in kilowatt-hours (kW·h) is required to generate this amount of H 2 (1 W = 1 J/s, 1 J = 1 C·V, and 1 kW·h = 3.6 × 106 J)?(e) If the cell is 88.0% efficient and electricity costs $0.123 per kW·h, what is the cost of producing the amount of H2 equivalent to 1.00 gal of gasoline?

Problem

Gasoline is a mixture of hydrocarbons, but the heat released when it burns is close to that of octane, C8H18(l) (ΔH°f = −250.1 kJ/mol). Research is underway to use H 2 from the electrolysis of water in fuel cells to power cars instead of gasoline.

(a) Calculate ΔH° when 1.00 gal of gasoline (d = 0.7028 g/mL) burns to produce carbon dioxide gas and water vapor.

(b) How many liters of H2 at 25°C and 1.00 atm must burn to produce this quantity of energy?

(c) How long would it take to produce this amount of H 2 by electrolysis with a current of 1.00 × 10 3 A at 6.00 V?

(d) How much power in kilowatt-hours (kW·h) is required to generate this amount of H 2 (1 W = 1 J/s, 1 J = 1 C·V, and 1 kW·h = 3.6 × 106 J)?

(e) If the cell is 88.0% efficient and electricity costs $0.123 per kW·h, what is the cost of producing the amount of H2 equivalent to 1.00 gal of gasoline?