Pure substances have a ... melting and boiling point.

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $24.99Unlock all

Study for the IGCSE Edexcel Chemistry Test. Access flashcards and multiple choice questions with hints and explanations. Get ready for your exam!

Multiple Choice

Pure substances have a ... melting and boiling point.

Explanation:
Melting and boiling points are set by the energy needed to overcome the forces holding a substance together. For a pure substance, every particle is the same, so there is a single, specific temperature at which the solid changes to a liquid and a single, specific temperature at which it boils (at a given pressure). This gives definite, fixed points. If there are impurities, the uniform structure is disturbed, so these phase changes occur over a range of temperatures rather than at one exact point. That’s why pure substances have fixed melting and boiling points.

Melting and boiling points are set by the energy needed to overcome the forces holding a substance together. For a pure substance, every particle is the same, so there is a single, specific temperature at which the solid changes to a liquid and a single, specific temperature at which it boils (at a given pressure). This gives definite, fixed points. If there are impurities, the uniform structure is disturbed, so these phase changes occur over a range of temperatures rather than at one exact point. That’s why pure substances have fixed melting and boiling points.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy