Which equation correctly relates the number of moles of a solute (n) to its mass (m) and molar mass (M)?

• A. n = m + M
• B. n = m / M
• C. n = M / m
• D. n = m × M

Answer: (B)

Verified step by step guidance

1. Understand the relationship between moles, mass, and molar mass: The number of moles (n) of a substance is defined as the ratio of the mass of the substance (m) to its molar mass (M).
2. Recall the formula that connects these quantities: \(n = \frac{m}{M}\), where \(n\) is the number of moles, \(m\) is the mass in grams, and \(M\) is the molar mass in grams per mole.
3. Recognize that this formula means you divide the mass of the solute by its molar mass to find how many moles are present.
4. Evaluate the other options: addition (\(n = m + M\)), division reversed (\(n = M / m\)), and multiplication (\(n = m \times M\)) do not correctly represent the relationship between these quantities.
5. Conclude that the correct equation relating moles, mass, and molar mass is \(n = \frac{m}{M}\).