Lecture Tools of analytical chemistry Volumetric Volumetricflasks flasksare are calibrated to contain calibrated to contain an anaccurate accuratevolume volume See the inside See the insideback back cover coverof ofthe thetext textfor for tolerances of Class tolerances of ClassAA volumetric volumetricglassware glassware Volumetric Volumetricpipets pipetsaccurately accuratelydeliver deliveraafixed fixedvolume volume AAsmall smallvolume volumeremains remainsin inthe thetip tip Volumetric flask Transfer or volumetric pipets Measuring pipets ©Gary Christian, Analytical Chemistry, 6th Ed (Wiley) Hamilton microliter syringe These Thesesyringe syringepipets pipetscan canreproducibly reproduciblydeliver deliveraaselected selectedvolume volume They Theycome comein infixed fixedand andvariable variablevolumes volumes The Theplastic plastictips tipsare aredisposable disposable Fig 2.12 Single-channel and multichannel digital displacement pipets and microwell plates ©Gary Christian, Analytical Chemistry, 6th Ed (Wiley) AA50-mL 50-mLburet buretisismarked markedin in0.1 0.1mL mLincrements increments You Youinterpolate interpolateto to0.01 0.01mL, mL,good goodto toabout about±0.02 ±0.02mL mL Two Tworeadings readingsare aretaken takenfor forevery everyvolume volumemeasurement measurement Typical buret How to read the markings of glassware? How to read the liquid level? How to clean glassware? How to prepare solutions? Stock solutions: Weigh (or measure an appropriate volume for liquid) Dissolve Bring to desired volume Preparing solutions by dilution: - Co is the stock solution’s concentration - Vo is the volume of stock solution being diluted - Cd is the dilute solution’s concentration - Vd is the volume of the dilute solution Whats’ the volume of 1000 ppm stock solution of Cu2+ needed to prepare 100 mL of 15 ppm solution of Cu 2+? C0V0 = CdVd 1000ppm x V0 = 15ppmx100 mL V0 = 1.5 mL Problems A) A laboratory procedure calls for 250 mL of an approximately 0.10 M solution of H2C2O4 Describe how you would prepare this solution using solid H2C2O4•2H2O B) A laboratory procedure calls for 250 mL of an approximately 0.10 M solution of HCl Describe how you would prepare this solution using a stock solution of concentrated HCl (C% = 37.5%; d = 1.19 g/ml) Homework 2) a) What is the concentration (expressed as mol/L = M) of NaCl when 32.0 g of NaCl is dissolved in water and diluted to 0.500 L? b) How many grams of methanol (CH3OH, formula weight = 32.04) are contained in 0.100 L of 1.71 M aqueous methanol? c) Any dilute aqueous solution has a density near 1.00 g/mL Suppose the solution contains ppm of solute; express the concentration of solute in g/L, mg/L, g/mL and mg/mL 3) Problem 4, Chapter 2, Harvey’s text book 4) Read Chapter Characterisation of data * sources of errors, how to eliminate errors.* The importance of stastical analysis, Gaussian distribution vs t-distribution ... accuratevolume volume See the inside See the insideback back cover coverof ofthe thetext textfor for tolerances of Class tolerances of ClassAA volumetric volumetricglassware glassware Volumetric Volumetricpipets... is the volume of stock solution being diluted - Cd is the dilute solution’s concentration - Vd is the volume of the dilute solution Whats’ the volume of 1000 ppm stock solution of Cu2+ needed... 100 mL of 15 ppm solution of Cu 2+? C0V0 = CdVd 1000ppm x V0 = 15ppmx100 mL V0 = 1.5 mL Problems A) A laboratory procedure calls for 250 mL of an approximately 0.10 M solution of H2C2O4