Calculating concentrations

1. Calculating concentrations

2. Different ways to express concentration: • Number of grams of solute per liter of solution (g/L) • Number of grams of solute per 100 ml of solution (%mass /volume =%m/V) • Number of millilitres of solute per 100 ml of solution (% volume/volume =%V/V) • Number of grams of solute per 100 grams of solution (% mass/ mass =%m/m) amount solute amount solution c =

3. grams of solute per liter of solution (g/L) in g in L amount solute mass of solute m amount solution volume of solution v c = c = c =

6. conversions 1.000 L = 1000 mL 100mL 0.100 L = 0.010L 10mL = 1mL = 0.001L 1.000 g 1000 mg = 0.100 g 100 mg = 0.010 g = 10mg 1mg 0.001g =

7. formula: 19 g sugar 19 g c = known: 0.2 L m = 19 g c = 95 g /L v = 200 ml = 0.2 L formula: mg known: 0.0535 g m m c = m = 53.5 mg 1 L v v c = c = = 0.0535 g c = 0.0535 g /L v = 1 L

8. example • How much sugar do you need if you want to make 20 ml of a sugar solution with a concentration of 50 g/L? known: formula: c = 50 g/L xg 50 g/L = v = 20 mL = 0.02 L 0.02 L m x = 1 g m = ? v m = 1 g c =

9. Different ways to express concentration: • Number of grams of solute per liter of solution (g/L) • Number of grams of solute per 100 ml of solution (%mass /volume =%m/v) • Number of millilitres of solute per 100 ml of solution (% volume/volume =%v/v) • Number of grams of solute per 100 grams of solution (% mass/ mass =%m/m) amount solute amount solution c =

10. grams of solute per 100 ml of solution:% m/v • 3.25 % MF  • 1 % MF  3.25 g milk fat 100 ml milk 1 g milk fat 100 ml milk amount solute amount solution c =

11. grams of solute per 100 ml of solution:% m/v 0.243 g Sodium fluoride 100 ml of tooth paste

12. example • Determine the concentration of a solution of 20 g solute in 250 mL final solution in % m/v. known: formula: m = 20 g v = 250 mL x g 20 g = c = xg /100 mL = x %m/v 100 mL 250 mL 20 g × 100 mL xg = 250 mL m c = 8 %m/v v x = 8 g c =

13. Different ways to express concentration: • Number of grams of solute per liter of solution (g/L) • Number of grams of solute per 100 ml of solution (%mass /volume =%m/v) • Number of millilitres of solute per 100 ml of solution (% volume/volume =%v/v) • Number of grams of solute per 100 grams of solution (% mass/ mass =%m/m) amount solute amount solution c =

14. milliliters of solute per 100 ml of solution, %v/v 5 ml acetic acid 7.9 ml ethanol 100 ml of vinegar 100 ml of beer

15. example • How much ethanol (in mL) is there in a 750 mL bottle of wine with an alcohol concentration of 12 %v/v? known: c = 12 mL / 100 mL xmL 12 mL c = = v = 750 mL 750 mL 100 mL amount of solute = xmL x = 90 mL amount solute amount solution amount of solute in 750 mL = 90 mL c =

16. Different ways to express concentration: • Number of grams of solute per liter of solution (g/L) • Number of grams of solute per 100 ml of solution (%mass /volume =%m/v) • Number of millilitres of solute per 100 ml of solution (% volume/volume =%v/v) • Number of grams of solute per 100 grams of solution (% mass/ mass =%m/m) amount solute amount solution c =

17. grams of solute / 100 g of solution: % m/m 18 Ka = 750 / 1000 75 g gold = 75 % m/m 100 g alloy

18. example • What is the % m/m carbon concentration of steel made by adding 3g of Carbon to 147 g of iron? known: amount of solute = 3 g 3 g xg c = = amount of solution = 147 + 3 g 150 g 100 g c = xg / 100 g x = 2 g amount solute c = 2 g / 100 g = 2 % m/m amount solution c =

19. Homework • Work book page 8 / 9; # 1, 2, 3, 6, 7 • Conversion work sheet

21. amount solute amount solution 100ml c =