What determines whether a reaction is endothermic or exothermic?

A The sign of ΔS

B The sign of ΔH: positive = endothermic, negative = exothermic

C The sign of ΔG

D The activation energy

✓ Correct Answer: Option B

ΔH > 0: endothermic (absorbs heat). ΔH < 0: exothermic (releases heat). Enthalpy change determines the heat flow direction.

💡 Why is B) the correct answer?

The correct answer to the question "What determines whether a reaction is endothermic or exothermic?" is Option B: The sign of ΔH: positive = endothermic, negative = exothermic.

The other options — A) The sign of ΔS, C) The sign of ΔG, D) The activation energy — are incorrect for this Everyday Science question. As explained above: ΔH > 0: endothermic (absorbs heat). ΔH < 0: exothermic (releases heat). Enthalpy change determines the heat flow direction.

📚 About This Everyday Science Practice Question

This 1-level Everyday Science question from the Chemistry - Elements & Compounds topic is part of One Paper Preparation's free exam preparation library. Each question includes the correct answer and a detailed explanation to help you understand the underlying concept, not just memorize the answer.

How to use this page: Read the question above, consider all four options (A through D), then check the highlighted correct answer and explanation. For active timed practice, start a free Everyday Science practice test or use flashcards for spaced repetition review.

Practice Everyday Science Quizzes → Browse All Questions Study Flashcards

What determines whether a reaction is endothermic or exothermic?

✓ Correct Answer: Option B

📚 About This Everyday Science Practice Question

Related Everyday Science Questions