Doubling the amount of CH4, while O2 is in excess, affects the enthalpy change ΔHrxn as follows.

Study for the Chemistry 1LD Test with comprehensive flashcards and multiple choice questions. Each question is accompanied by hints and detailed explanations to ensure your success. Prepare thoroughly for your exam!

Multiple Choice

Doubling the amount of CH4, while O2 is in excess, affects the enthalpy change ΔHrxn as follows.

Explanation:
The main idea is that ΔHrxn is the heat change for the reaction as written, per the stoichiometric amounts. When O2 is in excess, all the methane that can react does react, so the energy released per mole of CH4 burned stays the same. If you burn more CH4, the total heat released scales with the amount burned, but the enthalpy change per mole of reaction does not change. For example, one mole of CH4 combusted releases a fixed amount of energy (about -890 kJ), so burning two moles would release about twice that total energy, while the ΔHrxn value remains the same.

The main idea is that ΔHrxn is the heat change for the reaction as written, per the stoichiometric amounts. When O2 is in excess, all the methane that can react does react, so the energy released per mole of CH4 burned stays the same. If you burn more CH4, the total heat released scales with the amount burned, but the enthalpy change per mole of reaction does not change. For example, one mole of CH4 combusted releases a fixed amount of energy (about -890 kJ), so burning two moles would release about twice that total energy, while the ΔHrxn value remains the same.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy