Which of the following correctly describes how to calculate the molarity (M) of a solution?

• A. Multiply the number of moles of solute by the volume of solution in liters.
• B. Divide the mass of solute (in grams) by the volume of solution in liters.
• C. Divide the number of moles of solute by the volume of solution in liters.
• D. Divide the number of moles of solute by the volume of solution in milliliters.

Answer: (C)

Verified step by step guidance

1. Understand that molarity (M) is a measure of concentration defined as the number of moles of solute dissolved in one liter of solution.
2. Recall the formula for molarity: \(M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}\).
3. Note that the volume must be in liters, not milliliters, so if the volume is given in milliliters, convert it to liters by dividing by 1000.
4. Recognize that molarity is not calculated by multiplying moles by volume or by dividing mass by volume; it specifically involves moles and volume in liters.
5. Therefore, to find molarity, always divide the number of moles of solute by the volume of the solution expressed in liters.