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1 Chapter 0 = The Analytical Process You should read this chapter. Chapter 1= Chemical Measurements Section 1-1: SI Units and Prefixes You should know this material. Section 1-2: Conversion Between Units You should know this material. Section 1-3: Chemical Concentrations Solution = solute + solvent Solute = minor species in solution. Solvent = major species in solution. Most common solvent in CHM 3120: water. Concentration = amount of solute contained in a given volume or mass of solvent. 2 Molarity (M) M is the number of moles of solute per liter of solution M = moles of solute / liters of solution moles of solute = weight of solute (g)/formula weight of solute (g) or moles of solute = mass of solute (g)/formula mass of solute (g) or moles of solute = mass of solute (g)/molecular mass of solute (g) Example: How many grams of Boric Acid [B(OH)3, FM 61.83] should be used to make 2.00 L of 0.0500M solution? moles of solute = 2.00 L x 0.0500M = 0.1 mol mass of solute = moles of solute x formula mass mass of solute = 0.1 mol x 61.83 g = 6.183 g Electrolyte An electrolyte dissociates into ions in aqueous solution. A strong electrolyte dissociates almost completely. Example: MgCl2 Mg+ + MgCl+ After dissociation, 89% exists in the form of Mg2+ and 11% in the form of MgCl+ The molarity of a strong electrolyte is referred to as Formal Concentration (F) to indicate that the substance is really converted into other species in solution. 3 A weak electrolyte is partially split into ions in solution. Example: Acetic Acid, CH3CO2H Note: If you dissolve 0.01000 mol of acetic acid in 1.000L, you will have: a 0.01000 F solution or a 0.00959M solution Why? because 4.1% is dissociated into CH3CO2- (acetate ion) and 95.9% remains as CH3CO2H.... View Full Document

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