Molarity is defined as the number of moles per liter of solution (mol/L or M). The mass of a mole is equal to the atomic mass or molecular weight of the substance, expressed in grams/mole or daltons (gram molecular weight). Molecular weight is obtained by adding the atomic weights of each atom in the molecule. What is the molecular weight of glucose (C6H12O6)? (Atomic weights: carbon = 12, hydrogen = 1, oxygen = 16). Remember not to confuse molarity with molality, which is the number of moles of solute in 1 Kg of solvent (not total solution). The density of water is 1.00 g/ml, thus 1 Kg of water occupies a volume of 1 liter. Therefore, to make a 1 molar (1M) solution of NaCl you would take 1 mole of NaCl and add sufficient to make a final total volume of 1 liter. To make a 1 molal (1m) solution, you would simply add 1 liter of water to 1 mole of NaCl (total volume thus greater than 1 liter). However, the molality and molarity of dilute solutions are approximately equal. 1. How would you make up 0.5 liters of 3M NaCl solution? Osmolarity is defined as the concentration of a solution expressed in terms of osmotically active particles, or osmoles (osmol/L or OsM). Osmotically active particles are any solutes that contribute to the concentration gradient. These can be either intact, uncharged molecules or charged ions. Physiological solutions are very dilute and are usually expressed in milliosmoles/L (mOsM). To convert between molarity and osmolarity, use the following equation: osmolarity (osmol/L) = Molarity (mol/L) X # of dissociated particles/molecule 2. In the space below show how would you make up 400 ml of a 200 mOsm NaCl solution?