1. Lecture 2 Measurements Concentration Solution Preparation

6. Density kg/L = g/mL Density of water @4 o C 1.00 g/mL Specific gravity = density /(density of water @4 o C) Dimensionless! For diluted aqueous solutions, 1 kg  1 L Solutions

7. % ‘per cent’ 10g/1000g or 10g/L ppm ‘part per million’ 0.01 10 -2 1/1,000,000 10 -6 10g/kg (10 -6 g = 1  g) 1  g/g or 1 mg/L 1  g/mL 1 mg/kg ppb ‘part per billion’ 10 -9 (10 -9 g = 1 ng) 1 ng/g or 1  g/L 1 ng/mL 1  g/kg ppt - parts per thousand or parts per trillion!?

9. Molarity mole/L Molecular mass, formula mass. Molecular weight, formula weight FWgrams! Molarity  10  (X %) / FW Example: 1% HCl FW = 1+35.5=36.5 Molarity(1%HCl)= 10/36.5=0.27 M Molarity = 0.001  (X ppm) / FW Example: 10 ppm Pb FW=207.2 Molarity(10ppm Pb)= 10 -3  10/207.2=4.82  10 -5 M In diluted aqueous solutions:

10. Dilution 10 mL  200 ppm = 200 mL  10 ppm To make 200 mL of 10 ppm solution from 200 ppm, take 10 mL and dilute to the volume of 200 mL 5 mL  0.400 M = 100 mL  0.020 M To make 100 mL of 0.02M solution from 0.40 M, take 5 mL and dilute to the volume of 100 mL C 1  V 1 = C 2  V 2