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Solutions. PART V: Preparing Solutions. Review: Molarity. Molar concentration is the number of moles in 1.0 L of solution Molarity (mol/L) = moles solute_______ volume (L) of solution Also expressed as C = _ n__ V. Solutions can be made by:.
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Solutions PART V: Preparing Solutions
Review: Molarity • Molar concentration is the number of moles in 1.0 L of solution • Molarity (mol/L) = moles solute_______ volume (L) of solution • Also expressed as C = _n__ V
Solutions can be made by: • Dissolving a measured mass of a pure solute into a certain volume of solution (how is this done?) • Diluting solution of known concentration
Dilution • A less conc solution of a known conc solution by adding a measured amount of solvent • Volume inc = more diluted solution • The number of moles of solute does not change when a solution is diluted!!!
Dilution formula M1V1 = M2V2 M1V1 – refers to 1st (original) solution M2V2 – refers to 2nd solution • Just solve for unknown value
Ex: What volume of 16 mol/L HCl is needed to prepare 750 mL of 2.5 mol/L HCl? M1V1 = M2V2 (16 mol/L) V1 = (2.5 mol/L)(0.750L) V1 = 2.5 x 0.750 16 V1 = 0.117L You would need to add 117 mL of conc HCl to prepare the solution.