chap-13-2011W-a

# 088 mole h2o2 100 g soln 100g 105gml 952 ml 00952

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Unformatted text preview: 2O2 / 100 g solution 3.0 100 M? Mole of H2O2 /1 L of solution /1 3.0 g H2O2 mole = 3.0g ÷ 34.0mol/g = 0.088 mole H2O2 100 g soln 100g ÷ 1.05g/mL = 95.2 mL = 0.0952 L m o les o f so lu te ( m o l ) M= liters o f so l u tio n ( L ) 0 .0 8 8 m o l = = 0 .9 2 M 0 .0 5 9 2 L Which Which aqueous solution is best expressed in ppm? ppb? ppm? (a) 5 µg solute per L (b) 3.5 mg per kg (c) 50 g per m3 Analysis: For dilute aqueous solutions, dilute 1 g = 1 mL = 1 cm3 1 kg = 1000 g = 1000 mL = 1 L 1000 (a) 5 µg solute per L solution = 5 µg / 1 kg kg = (5×10-9 kg / 1 kg) =5.0× 10-9 = 5 ppb (b) 3.5 mg per kg = 3.5 mg / 1 kg = (3.5 × 10-6 kg / 1 kg) = 5.0× 10-6 = 3.5 ppm 5.0 3.5 (c) 50 g per m3 = 50 g / (102 cm)3 = 50 g / (106 cm3) (10 (10 = (50 g / 106 g) = 50× 10-6 = 50 ppm 10 50 Compare Mass% Compare Mass%, ppm and ppb and Which NaCl solution is most concentrated? 1 x10-3 M 1x10-2 % 1 ppm 1000 ppb ↓ ↓ ↓ ↓ 0.001 mole NaCl 1L (soln) 0.0585 g NaCl = 1000 ml (soln) 0.01 g NaCl 100 g (soln) = 1.0 ×10−4 = 5.85×10−5 g / ml ( 1g ∼ 1ml ) = 5.85×10−5 the highest! 1 g NaCl 1000 g NaCl NaCl 1000 6 9 10 g (soln) 10 g (soln) −6 = 1.0 ×10 −6 = 1.0 ×10 Mole Mole Fraction ( mf ) mf What is the mole fraction of each component in a solution of 36% HCl by mass? Sum of mole fractions of all components must = 1 36% HCl = 36 g HCl and 64 g H2O Mole of HCl = 3 6 g HCl ÷ 3 6.5 g/mole=0.99 mole Mole of H 2O = 64 g H 2O ÷ 18 g/mole=3.56 mole X HCl 0 .9 9 = = 0 .2 2 0 .9 9 + 3 .5 6 X H 2 O = 1 − 0 .2 2 = 0 .7 8 Molality Molality (m) Exercise: The ocean contains 19,000 ppm of chloride ion. What is the molality of this ion? m o les o f so lu te ( m o l ) M o la lity ( m ) = M a s s o f so lven t ( kg ) MCl− = 19000g ÷ 35.5 g/mole = 535 mole MH2O = 106g - 19000 g Cl- = 9.8×105g = 9.8×102kg mCl− = 535 mole (Cl- ) / 9.8×102kg H2O = 0.55 m Compare M, Compare M, mf and m and Which NaCl solution is most concentrated? 1 × 10-2 M 1 × 10-2 mf ↓ ↓ 0.01 mole NaCl 0.01 mole NaCl+0.99 mole H2O 0.01 mole NaCl 1000 mL (solu) −2 = 1.0 ×10 M = 0.01molNaCl 0.585g NaCl + 0.99mol ×18g / mol H2O 0.01molNaCl 0.01molNaCl ≈ 18.4 g solu 18.4ml solu ×10−3 L / ml = 0.54M = 1 × 10-2 m ↓ 0.01 mole NaCl 1000 g H2O Since: 1 g ~ 1mL ↓ 1000 g NaCl 106g solu 0.01 0.01 mole NaCl → 1000g ÷ 58.5g / mol 1000g + 0.585g(solu) 1000kg solu 0.01mol NaCl = 1000.585 g ÷1.0g / mL ≈ 17.1 mol NaCl 1000L 0.01mol NaCl = 1.000585 L = 1.71×10−2 mol / L = 0.009994M ≈ 0.01M the highest! 1000 ppm = 1.0 ×10−2 M the the same!...
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