1. White Board Review Practicing with Concentration Expressions Molarity Percent ppm © Mr. D. Scott; CHS

2. Determine the molarity of 250 mL of solution containing 35 g of NaOH. What you must remember: molarity = moles of solute per liter of solution = 35 g NaOH 0.250 Liters = 3.5 M NaOH Practicing with Concentrations Molarity © Mr. D. Scott; CHS

3. What volume of a 2.0 M solution will provide 18 g of NaOH? What you must remember: moles solute ÷ molarity = L volume = 18 g NaOH 0.45 mol NaOH = 0.23 L 0.45 mol NaOH or 230 mL of solution First find moles: Next, divide moles by molarity: Practicing with Concentrations Molarity © Mr. D. Scott; CHS

4. What mass of NaOH is needed to make 4.0 liters of a 0.75 M solution? What you must remember: L volume X molarity = moles solute = 4.0 L solution 3.0 mol NaOH = 120 g NaOH 3.0 mol NaOH First find moles solute: Next, multiply moles by molar mass: Practicing with Concentrations Molarity © Mr. D. Scott; CHS

5. Determine the molarity of 850 mL of solution containing 95 g of KCl. What you must remember: molarity = moles of solute per liter of solution = 95 g KCl 0.850 Liters = 1.5 M KCl Practicing with Concentrations Molarity © Mr. D. Scott; CHS

6. What volume of a 3.8 M solution will provide 120 g of LiF? What you must remember: moles solute ÷ molarity = L volume = 120 g LiF 4.63 mol LiF = 1.2 L 4.63 mol LiF First find moles: Next, divide moles by molarity: Practicing with Concentrations Molarity © Mr. D. Scott; CHS

7. Practicing with Concentrations Molarity What mass of NaSCN is needed to make 550 mL of a 2.4 M solution? What you must remember: L volume X molarity = moles solute = 0.55L solution1.32 mol NaSCN = 110 g NaSCN 1.32 mol NaSCN First find moles solute: Next, multiply moles by molar mass: © Mr. D. Scott; CHS

8. Determine the % w/v of 25 mL of solution containing 3.0 g of CsOH. What you must remember: % w/v = g of solute per mL of solution X 100 = 3.0 g CsOH 25 mL = 12 % w/v CsOH Practicing with Concentrations Percent © Mr. D. Scott; CHS x 10 2

9. What volume of a 6.2 % w/v solution will provide 32 g of KMnO 4 ? What you must remember: g solute ÷ % w/v = mL volume Practicing with Concentrations © Mr. D. Scott; CHS Percent = 520 mL KMnO 4 solution First interpret % w/v :Next, divide the g solute by the %: 32 g

10. Practicing with Concentrations What mass of NaClO is needed to make 150 mL of a 4.9 % w/v solution? What you must remember: % w/v = g/100mL and mL volume X % = g solute = 7.4 g NaClO X First interpret % w/v :Next, multiply by mL volume: © Mr. D. Scott; CHS Percent 150 mL

11. Determine the % w/v of 960 mL of solution containing 37 g of KClO 3. What you must remember: % w/v = g of solute per mL of solution X 100 = 37 g KClO 3 960 mL = 3.9 % w/v KClO 3 Practicing with Concentrations Percent © Mr. D. Scott; CHS x 10 2

12. What volume of a 0.55 % w/v solution will provide 2.5 g of KNO 2 ? What you must remember: g solute ÷ % w/v = mL volume Practicing with Concentrations © Mr. D. Scott; CHS Percent = 450 mL KNO 2 solution First interpret % w/v :Next, divide the g solute by the %: 2.5 g

13. Practicing with Concentrations What mass of NaSO 4 is needed to make 500. mL of a 1.0 % w/v solution? What you must remember: % w/v = g/100mL and mL volume X % = g solute = 5.0 g NaSO 4 X First interpret % w/v :Next, multiply by mL volume: © Mr. D. Scott; CHS Percent 500. mL

14. Calculate the concentration in ppm of 3250 mL of solution containing 0.25 g of NiSeO 3. What you must remember: ppm = g of solute per mL of solution X 10 6 = 0.25 g NiSeO 3 3250 mL = 77 ppm NiSeO 3 Practicing with Concentrations ppm © Mr. D. Scott; CHS x 10 6

15. What volume of a 320 ppm solution will provide 0.75 g of K 2 Cr 2 O 7 ? What you must remember: ppm = mg/L and mg solute ÷ ppm = L volume Practicing with Concentrations © Mr. D. Scott; CHS = 750 mg First interpret ppm:Next, convert g to mg: 0.75 g ppm Finally, divide mg solute by ppm: 750 mg = 2.3 L

16. Practicing with Concentrations What mass of MgSO 3 is needed to make 100. mL of a 38 ppm solution? What you must remember: ppm = mg/L and L volume X ppm = mg solute = 3.8 mg MgSO 3 X First interpret ppm:Next, multiply by L volume: © Mr. D. Scott; CHS 0.100 L ppm

17. Calculate the concentration in ppm of 25,000 mL of solution containing 1.0 g of KF. What you must remember: ppm = g of solute per mL of solution X 10 6 = 1.0 g KF 25,000 mL = 40. ppm KF Practicing with Concentrations ppm © Mr. D. Scott; CHS x 10 6

18. What volume of a 5.0 ppm solution will provide 1.0 g of NaCN? What you must remember: ppm = mg/L and mg solute ÷ ppm = L volume Practicing with Concentrations © Mr. D. Scott; CHS = 1000 mg First interpret ppm:Next, convert g to mg: 1.0 g ppm Finally, divide mg solute by ppm: 1000 mg = 2.0 x 10 2 L

19. Practicing with Concentrations What mass of FePO 4 is needed to make 500. mL of a 120 ppm solution? What you must remember: ppm = mg/L and L volume X ppm = mg solute = 60. mg FePO 4 X First interpret ppm:Next, multiply by L volume: © Mr. D. Scott; CHS 0.500 L ppm