1. Saturday Study Session 1 1 st Class Reactions

2. Opening activity – Solid calcium oxide is added to water CaO + H 2 O  Ca(OH) 2 molecular equation CaO + H 2 O  Ca 2+ + 2 (OH) - net ionic – Potassium chlorate(s) is heated 2KClO 3  2KCl + 3O 2 molecular and ionic – Calcium carbonate(s) is heated CaCO 3  CaO + CO 2 molecular and ionic – Sodium hydroxide(aq) is heated 2NaOH  Na 2 O + H 2 O molecular 2Na + + 2(OH) -  Na 2 O + H 2 O ionic

3. Aluminum metal is added to solution of copper II chloride 2Al + 3CuCl 2  2 AlCl 3 + 3Cu molecular 2Al + 3Cu 2+  2Al 3+ + 3 Cu ionic – Fluorine gas is bubbled into solution of sodium bromide F 2 + 2NaBr  2NaF + Br 2 molecular F 2 + 2Br -  2F - + Br 2 – Solutions of Hydrofluoric acid is added to ammonium hydroxide HF + NH 4 OH  NH 4 F + H 2 O molecular HF + NH 4 OH  NH 4 + + F - + H 2 O ionic – Butane is burned in Air 2C 4 H 10 + 13O 2  8CO 2 + 10H 2 O molecular and ionic

4. Formula Equation (Molecular Equation) Gives the overall reaction stoichiometry but not necessarily the actual forms of the reactants and products in solution. Reactants and products generally shown as compounds. Use solubility rules to determine which compounds are aqueous and which compounds are solids. AgNO 3 (aq) + NaCl(aq) AgCl(s) + NaNO 3 (aq) Copyright © Cengage Learning. All rights reserved 4

5. Complete Ionic Equation All substances that are strong electrolytes are represented as ions. Ag + (aq) + NO 3  (aq) + Na + (aq) + Cl  (aq) AgCl(s) + Na + (aq) + NO 3  (aq) Copyright © Cengage Learning. All rights reserved 5

6. Electrolytes

7. HCl --- Strong electrolyte 100% dissociation

8. Net Ionic Equation Includes only those solution components undergoing a change. – Show only components that actually react. Ag + (aq) + Cl  (aq)  AgCl(s) Spectator ions are not included (ions that do not participate directly in the reaction). – Na + and NO 3  are spectator ions. Copyright © Cengage Learning. All rights reserved 8

9. Precipitant

11. White Precipitant AgCl, Mg(OH) 2, BaSO 4

12. Stoichiometry Exercise 1 A 500.0-g sample of potassium phosphate is dissolved in enough water to make 1.50 L of solution. What is the molarity of the solution? 1.57 M

13. Exercise 2 What is the minimum volume of a 2.00 M NaOH solution needed to make 150.0 mL of a 0.800 M NaOH solution? 60.0 mL

14. 10.0 mL of a 0.30 M sodium phosphate solution reacts with 20.0 mL of a 0.20 M lead(II) nitrate solution (assume no volume change). – What precipitate will form? lead(II) phosphate, Pb 3 (PO 4 ) 2 – What mass of precipitate will form? 1.1 g Pb 3 (PO 4 ) 2 Copyright © Cengage Learning. All rights reserved 14 (Part I) Exercise 3

15. 10.0 mL of a 0.30 M sodium phosphate solution reacts with 20.0 mL of a 0.20 M lead(II) nitrate solution (assume no volume change). – What is the concentration of nitrate ions left in solution after the reaction is complete? Nitrate 0.27 M Copyright © Cengage Learning. All rights reserved 15 (Part II) Exercise 4

16. 10.0 mL of a 0.30 M sodium phosphate solution reacts with 20.0 mL of a 0.20 M lead(II) nitrate solution (assume no volume change). – What is the concentration of phosphate ions left in solution after the reaction is complete? 0.011 M Copyright © Cengage Learning. All rights reserved 16 (Part III)

17. Which of the following ions form compounds with Pb 2+ that are generally soluble in water? a)S 2– b)Cl – c)NO 3 – d)SO 4 2– e)Na + Copyright © Cengage Learning. All rights reserved 17

18. Which of the following solutions contains the greatest number of ions? a) 400.0 mL of 0.10 M NaCl. b) 300.0 mL of 0.10 M CaCl 2. c) 200.0 mL of 0.10 M FeCl 3. d) 800.0 mL of 0.10 M sucrose. Copyright © Cengage Learning. All rights reserved 18

19. A 0.50 M solution of sodium chloride in an open beaker sits on a lab bench. Which of the following would decrease the concentration of the salt solution? a)Add water to the solution. b)Pour some of the solution down the sink drain. c)Add more sodium chloride to the solution. d)Let the solution sit out in the open air for a couple of days. e)At least two of the above would decrease the concentration of the salt solution. Copyright © Cengage Learning. All rights reserved 19

20. After completing an experiment to determine gravimetrically the percentage of water in a hydrate, a student reported a value of 38 percent. The correct value for the percentage of water in the hydrate is 51 percent. Which of the following is the most likely explanation for this difference? a.Strong initial heating caused some of the hydrate sample to spatter out of the crucible. b.The dehydrated sample absorbed moisture after heating. c.The amount of the hydrate sample used was too small. d.The crucible was not heated to constant mass before use. e.Excess heating caused the dehydrated sample to decompose.

21. Acid–Base Reactions (Brønsted–Lowry) Acid—proton donor Base—proton acceptor Conjugate Acid – formed when base gains a H + Conjugate Base – formed when acid loses a H + HF + NH 3  NH 4 + + F - Acid Base Conjugate Conjugate Acid Base Copyright © Cengage Learning. All rights reserved 21

22. For the titration of sulfuric acid (H 2 SO 4 ) with sodium hydroxide (NaOH), how many moles of sodium hydroxide would be required to react with 1.00 L of 0.500 M sulfuric acid to reach the endpoint? 1.00 mol NaOH Copyright © Cengage Learning. All rights reserved 22

23. Titration – Laboratory Procedure Redox reaction or acid base Neutralization reaction To determine the concentration of a solution

24. Redox Characteristics Transfer of electrons Transfer may occur to form ions Oxidation – increase in oxidation state (loss of electrons); reducing agent Reduction – decrease in oxidation state (gain of electrons); oxidizing agent Copyright © Cengage Learning. All rights reserved 24

25. Reaction of Sodium and Chlorine Copyright © Cengage Learning. All rights reserved 25

26. Find the oxidation states for each of the elements in each of the following compounds: K 2 Cr 2 O 7 CO 3 2- MnO 2 PCl 5 SF 4 Copyright © Cengage Learning. All rights reserved 26 K = +1; Cr = +6; O = –2 C = +4; O = –2 Mn = +4; O = –2 P = +5; Cl = –1 S = +4; F = –1

27. Which of the following are oxidation-reduction reactions? Identify the substance oxidized and reduced. a)Zn(s) + 2HCl(aq)  ZnCl 2 (aq) + H 2 (g) b)Cr 2 O 7 2- (aq) + 2OH - (aq)  2CrO 4 2- (aq) + H 2 O(l) c)2CuCl(aq)  CuCl 2 (aq) + Cu(s) Copyright © Cengage Learning. All rights reserved

28. Free Response 2003B Answer the following questions that relate to chemical reactions. (a) Iron(III) oxide can be reduced with carbon monoxide according to the following equation. Fe2O3(s) + 3 CO(g) → 2 Fe(s) + 3 CO2(g) A 16.2 L sample of CO(g) at 1.50 atm and 200.°C is combined with 15.39 g of Fe2O3(s). (i)How many moles of CO(g) are available for the reaction? (ii) What is the limiting reactant for the reaction? Justify your answer with calculations. (iii) How many moles of Fe(s) are formed in the reaction?

29. . A 0.345 g sample of anhydrous BeC 2 O 4, which contains an inert impurity, was dissolved in sufficient Water to produce 100.0 mL of solution. A 20.0 mL portion of this solution was titrated with KMnO 4 (aq). The balanced equation for the reaction that occurs is: 16H + (aq) + 2 MnO 4 - (aq) + 5 C 2 O 4 2- (aq)  2 Mn 2+ (aq) + 10 CO 2 (g) + 8 H 2 O(l) The volume of the 0.0150 M KMnO 4 (aq) required to reach the equivalence point of the titration was 17.80 mL i. Identify the the substance oxidized and the substance reduced in the titration reaction. ii. For the titration at the equivalence point, calculate the number of moles of each of the following that reacted: a. MnO 4 - b. C 2 O 4 2- iii. Calculate the total number of moles of C 2 O 4 2- that were present in the 100.0 mL of prepared solution. iv. Calculate the mass percent of the BeC 2 O 4 in the impure 0.345 g sample