1. Units of Concentration The analytical chemist’s nightmare!

2. SI Units

3. Concentration Units

4. Prefixes

5. Calculations l The Mole Concept v The amount of substance which contains as many entities as there are atoms in 12 grams of 12 C. l One Mole = 6.023 x 10 23 l Avogadro’s Number

7. Calculations l Molar Solutions v xM = mass/RMM in 1000ml

8. Calculations l Molar Solutions to gdm -3 v mass = xM x RMM in 1000ml

9. Calculations l Molar Solutions to ppm v 1ppm = 1mg per kg v mass = xM x RMM in 1000ml v mass (g) x 1000 = mass (mg)

10. Calculations l Percentage Concentrations %(w/w) = x 100 Mass of Solute Total Mass of Solution %(v/v) = x 100 Volume of Solute Total Volume of Solution %(w/v) = x 100 Mass of Solute 100ml of Solution

11. Calculations l 10% Ethanol in Water v 10% (w/v) = 10g per 100ml = 100g in 1000ml v 100g / 46.07 = 2.17M v 10% (v/v) =10ml per 100ml = 100ml in 1000ml v 100ml x 0.79 = 79g 79g / 46.07 = 1.71M v 10% (w/w) = 10g per 100g = 100g in 1000g v 100g / 0.79 = 126.6ml126.6 + 900 = 1026.6ml v 100 x 1000/1026.6 = 97.4g 97.4g / 47.06 = 2.11M

12. Calculations l %Concentration to Molarity v 1% (w/v) = 1g per 100ml = 10g in 1000ml v xM = mass/RMM in 1000ml

13. Calculations l Titrations v M A V A = M B V B