What does a 1 molar (1 M) solution represent?

What does a 1 molar (1 M) solution represent?

• A. Moles per liter
• B. Molecular weight in grams per liter
• C. Grams per liter per mole
• D. Grams per mole per liter

Answer: (B)

Molarity measures how many particles are in a liter of solution. A 1 M solution has 1 mole of solute in every liter, so its units are moles per liter (mol/L). Grams per liter is a different way to express concentration called mass concentration. It depends on the solute’s molar mass: since 1 mole of a substance weighs its molar mass in grams, 1 M corresponds to a mass concentration of the solute equal to its molar mass in g/L. For example, 1 M NaCl contains about 58.44 g of NaCl per liter. So the general definition of 1 M is mol/L, not grams per liter.

Molarity measures how many particles are in a liter of solution. A 1 M solution has 1 mole of solute in every liter, so its units are moles per liter (mol/L).

Grams per liter is a different way to express concentration called mass concentration. It depends on the solute’s molar mass: since 1 mole of a substance weighs its molar mass in grams, 1 M corresponds to a mass concentration of the solute equal to its molar mass in g/L. For example, 1 M NaCl contains about 58.44 g of NaCl per liter. So the general definition of 1 M is mol/L, not grams per liter.