1. Chemical Reactions What’s in the Bottles?

2. What’s in the Bottles • Qualitative Analysis • Identification • Not quantitation • Volumes of reagents not critical • A basic understanding of double-displacement reactions important

3. Evidences of a Chemical Reaction • Color change • Precipitate formation • Temperature change • Gas evolution • Formation of a weak electrolyte

4. Solubility Rules (abbreviated list) • Group 1 compounds are soluble • All nitrates are soluble • Most chlorides are soluble • Exceptions are Pb2+, Ag+, Hg22+ • Most sulfates are soluble • Exceptions are Sr, Ba, Pb, Hg22+ Refer to Lab Manual Appendix 4 for more complete list

5. Solubility Reactions KNO3(aq) K+(aq)+NO3-(aq) Cu(NO3)2(aq)  Cu2+(aq) +2NO3-(aq) H2O H2O

6. 3 Representations of Chemical Equations • Whole molecular equation Pb(NO3)2(aq) + 2 KI(aq)PbI2(s) + 2 KNO3(aq) • Whole ionic equation Pb2+(aq) + 2 NO3-(aq) + 2 K+(aq) + 2 I-(aq)PbI2(s) + 2 K+(aq) + 2NO3-(aq) • Net ionic equation Pb2+(aq) + 2 I-(aq) PbI2(s) • Whole molecular equation Pb(NO3)2(aq) + 2 KI(aq)PbI2(s) + 2 KNO3(aq) • Whole ionic equation Pb2+(aq)+ 2 NO3-(aq) + 2 K+(aq) + 2 I-(aq)PbI2(s)+ 2 K+(aq) + 2NO3-(aq) • Net ionic equation • Whole molecular equation Pb(NO3)2(aq) + 2 KI(aq)PbI2(s) + 2 KNO3(aq) • Whole ionic equation Pb2+(aq) + 2 NO3-(aq) + 2 K+(aq) + 2 I-(aq)PbI2(s) + 2 K+(aq) + 2NO3-(aq) • Net ionic equation Pb2+(aq) + 2 I-(aq) PbI2(s) Remove the spectator ions

7. Some notes about this week’s lab • Concentrated acids: BE CAREFUL • AgNO3 will stain your skin—wear gloves • All waste must be collected in designated containers • Use well plates • One pipette per bottle please! • Test for temperature change if no other indications • Determine unknowns BEFORE leaving lab

8. B D ase lue Aci Re Some notes about this week’s lab Litmus Paper: Base turns red paper blue Acid turns blue paper red Cute, huh? Note: use a glass stir rod to spot the litmus paper—DO NOT dip litmus into solution

9. Some Example Reactions • Whole molecular reaction (Double-Displacement) • 2 AgNO3(aq) + ZnCl2(aq) • Zn(NO3)2 + 2 AgCl (aq) (s) Will a reaction occur? Write possible products. Will a precipitate form? Check the solubility rules.

10. Some Example Reactions Brown Solid White Solid NR NR NR Temp Increase

11. Some notes about groups and reports • Group Dynamics • It is each members responsibility to make sure that ALL group members understand the material • Play well with others!

12. Some notes about groups and reports This investigation, Author 1: Introduction and Conclusion 2: Discussion 3: Data/Results and Experimental This investigation, Author B: Introduction, Conclusion, Data/Results A: Discussion and Experimental

13. Procedure Design Today With your group you should develop a procedure that will allow you to determine which set of bottles you have been assigned. You must create complete reaction tables (chemical equations with expected products, if any) for 2 of the possible groups (you choose which two). Note: You must complete the ID of the bottle group assigned before leaving lab.

15. Exit Quiz There is no exit quiz this week Have a great week!