← back to the Substrate Record

qid 4279 · chemistry

Question: When heated to 600°C, acetone (CH_3COCH_3) decomposes to give CO and various hydrocarbons. The reaction is found to be first order in acetone concentration with a half-life of 81 sec. Given at 600°Ca 1-liter container into which acetone is injected at 0.48 atm, approximate how long would it take for the acetone pressure to drop to 0.45 atm?

  1. 20 sec
  2. 40 sec
  3. 120 sec
  4. 7.5 sec
  5. 8.56 sec
  6. 2.7 sec
  7. 0.693 sec
  8. 162 sec
  9. 81 sec
  10. 12 sec

Our answer: D. 7.5 sec Source quote machine-checked (exact quote)

A machine check confirms the quoted words appear at the source. A person has not yet reviewed these. EARN MARKS as a Human Reviewer

How it was answered

Multi-step solver (maze), replayed by code

card: maze · card sha256 665342777ac0b730…

Current source

OpenStax, Chemistry 2e, Section 12.4 Integrated Rate Laws

https://openstax.org/books/chemistry-2e/pages/12-4-integrated-rate-laws

“The decomposition of hydrogen peroxide is a first-order reaction, and, as can be shown, the half-life of a first-order reaction is independent of the concentration of the reactant.”

Source quote machine-checked (exact quote)

retrieved 2026-09-18T00:09:54.704Z

page text sha256 d5c01cd93593797f… · content sha256 35d7435d262d19b5…

addendum maze_qid4279_b4_maze_input_ADDENDUM_source_rs20260918T000954Z · sha256 6c11abb08830b7e3… · replaces the version below, addendum sha256 4cb505a7ff30bd46…

Earlier version (superseded)

https://openstax.org/books/chemistry-2e/pages/12-4-integrated-rate-laws

Source weak (http_get_200_text_and_question_terms)

retrieved 2026-09-17T23:23:13.460Z

page text sha256 f657d4077942f8a6… · content sha256 —

addendum maze_qid4279_b4_maze_input_ADDENDUM_source_bf20260917T232313Z · sha256 4cb505a7ff30bd46… · replaces the version below, addendum sha256 e50157ac11e0be36…

Earlier version (superseded)

No public source has been found for this card yet (3 places checked internally).

addendum maze_qid4279_b4_maze_input_ADDENDUM_source · sha256 e50157ac11e0be36…

If you have a Citable Source to dispute or challenge this, ADD IT so we can correct the answer by appending, never deleting. — hello@lianabanyan.com