Analytical Chem istry - DePauw University

Chapter 2 Basic Tools of Analytical Chemistry39050 . mol NaCl 58.43 gNaCl 10 6 µ g 1 L× × × = 29 . × 10 3 µg/mLL molNaCl g 1000 mL025 . mol SrCl 158.5 gSrCl 10 62 2µg 1 L× × × = 40 . × 10 3 µ g/mLL molNaCl g 1000 mLThe solution of SrCl 2 has the larger concentration when expressed in μg/mL instead of in mol/L.Click here to return to the chapter.Practice Exercise 2.3The concentrations of K + and SO 2– 4 are+15 . gK SO 1 molK SO2 4 2 42 molK× × = 34 . 4× 10−0. 500 L 174.3 gK SO molK SO2 42 42MK+2−15 . gK SO 1 molK SO 1mol SO2 4 2 44× × = 17 . 2×100. 500 L 174.3 gK SO molK SO2 42 4The pK and pSO 4 values arepK = –log(3.44× 10 –2 ) = 1.46pSO 4 = –log(1.72 × 10 -2 ) = 1.76Click here to return to the chapter.Practice Exercise 2.4First, we find the moles of AgBr1mol AgBr0.250 gAgBr × = 133 . 1× 10 −3187.8 gAgBrand then the moles and volume of Na 2 S 2 O 332mol Na SO133 . 1× 10 −2 2 3molAgBr × = 2.66210molAgBr31 L266 . 2× 10− molNaSO ×2 2 30.0138 molNaSO2 2 3Click here to return to the chapter.Practice Exercise 2.5Preparing 500 mL of 0.1250 M KBrO 3 requiresMSO−2 2−4× −31000 mL× = 193 mLL