How is the number of moles calculated from mass and molar mass?

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 IMAT Chemistry Exam. Access flashcards and multiple choice questions; hints and explanations included for each question. Prepare effectively for your exam.

Multiple Choice

How is the number of moles calculated from mass and molar mass?

Explanation:
The number of moles comes from thinking of molar mass as the mass per one mole. If you have a mass m in grams and a molar mass M in g/mol, the amount in moles is n = m / M. The units confirm this: grams divided by grams per mole leaves moles. For example, 24 g of a substance with a molar mass of 12.0 g/mol gives 24 / 12.0 = 2.0 mol. If you have 50 g with a molar mass of 58.44 g/mol (like NaCl), you get 50 / 58.44 ≈ 0.856 mol. Options that multiply mass by molar mass or divide molar mass by mass don’t yield a mole count, and using volume in this ratio isn’t the correct way to convert mass to moles.

The number of moles comes from thinking of molar mass as the mass per one mole. If you have a mass m in grams and a molar mass M in g/mol, the amount in moles is n = m / M. The units confirm this: grams divided by grams per mole leaves moles.

For example, 24 g of a substance with a molar mass of 12.0 g/mol gives 24 / 12.0 = 2.0 mol. If you have 50 g with a molar mass of 58.44 g/mol (like NaCl), you get 50 / 58.44 ≈ 0.856 mol.

Options that multiply mass by molar mass or divide molar mass by mass don’t yield a mole count, and using volume in this ratio isn’t the correct way to convert mass to moles.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy