Final answer:
Molarity (M) is the number of moles of solute per liter of solution (mols/L). It is used for calculating the number of moles in a given volume of solution or deriving concentration from mass and volume measurements. Differentiate it from molality, which is moles of solute per kilogram of solvent.
Step-by-step explanation:
Molarity (M) is a unit of concentration used in Chemistry, defined as the number of moles of solute dissolved in one liter of solution. This means that the correct answer to the student's question is (b) mols/L. To further assist with understanding, if you have a 3.0 M solution of a substance like sucrose, it indicates there are three moles of sucrose in every liter of that solution.
Moreover, it is vital to understand that molarity calculations can be used to determine the number of moles of solute by multiplying the molarity by the volume in liters. For example, if you know the molarity of a solution and the volume of the liquid, you can calculate how many moles of solute it contains. Conversely, if you have the amount of solute in grams, you can divide this by the molar mass to find the moles, and dividing by the volume in liters provides the molarity.
It is also essential to differentiate molarity from molality, which is another unit of concentration, defined as the number of moles of solute per kilogram of solvent (not per liter of solution).
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