Solutions!!! Chem 332 – O’Dette

What is a solution? A homogeneous mixture of a solute and solvent Solvent : major component, largest component of substance present Solute : minor component Solution : solute + solvent

Solutions Type Example Solvent Solute Gas Air N2 (78%) O2 (21%) Liquid Vinegar H2O Acetic Acid Solid Brass Cu (70%) Zn (30%)

Molarity (M) Molarity = moles of solute Used to express the concentration of a solution using specific units Used as a conversion factor to calculate moles and volume liters of solution

Example #1 3.0 moles of KBr are present in 0.40 L of solution. Find the molarity. 3.0 moles KBr 7.5 moles KBr 7.5 M KBr = = 0.40 L KBr 1 L KBr

Example #2 Find the number of moles of the solute in 2 L of a 3.0 M NaCl solution. C.F. = 3.0 moles NaCl 1 L NaCl 2 L NaCl 3 moles NaCl = 6 moles NaCl x 1 L NaCl

Example # 3 What volume of solution can be made from 6 moles KNO3 to produce a 0.60 M concentration? Conversion Factor 6 moles KNO3 x 1 L KNO3 = 10 L KNO3 0.60 mole KNO3