Predicting Redox Reactions 9.3.

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Presentation transcript:

Predicting Redox Reactions 9.3

Predicting Spontaneous Reactions Using the Standard Reduction Chart Does Au3+ react with Cl-? If it does write the spontaneous reaction.

The top reaction is written forward- reduction The bottom reaction is written in reverse- oxidation (Au3+ + 3e-  Au(s)) 2 (2Cl-  Cl2(g) + 2e-) 3 2Au3+ + 6Cl-  3Cl2(g) + 2Au(s)

Does Ag+ react with Br-?

nonspontaneous

Some ions are on both sides of the table and are oxidizing or reducing agents. For example: Fe  Fe2+  Fe3+ Sn  Sn2+  Sn4+ Cu  Cu+  Cu2+

Does Sn2+ react with Cr?

spontaneous 3 (Sn2+ + 2e-  Sn(s)) 2 (Cr(s)  Cr3+ + 3e-) Check both spontaneous 3 (Sn2+ + 2e-  Sn(s)) 2 (Cr(s)  Cr3+ + 3e-) 2Cr (s) + 3Sn2+  2Cr3+ + 3Sn(s)

Can you keep HCl in a Cu container? Explain!

nonspontaneous

Can you keep HCl in a Cu container? Explain! Yes, nonspontaneous. H+ is a weaker oxidizing agent than Cu2+ and Cu+.

Can you keep HCl in a Zn container? Explain!

Spontaneous- no H+ is a stronger oxidizing agent than Zn2+

Write the spontaneous reaction. 2H+ + 2e-  H2(g) Zn(s)  Zn2+ + 2e- 2H+ + Zn(s)  H2(g) + Zn2+

Can you keep HNO3 in a Au container? Explain!

Can you keep HNO3 in a Au container? Explain! Yes, nonspontaneous. HNO3 is a weaker oxidizing agent than Au3+.

Can you keep HNO3 in a Cu container? Explain!

Take the strongest ox agent- higher Take the strongest red agent- lower

Can you keep HNO3 in a Cu container? No, spontaneous. HNO3 is a stronger oxidizing agent than Cu2+. Write the spontaneous reaction. NO3- + 4H+ + 3e-  NO(g) + 2H2O x 2 Cu(s)  Cu2+ + 2e- x 3 2NO3- + 8H+ + 3Cu(s)  2NO(g) + 4H2O + 3Cu2+

nonspontaneous- both on same side Does Au3+ react with Fe3+?

spontaneousdownhill Does Fe3+ react with Pb?

nonspontaneous- uphill Does Cl2 react with F-?

spontaneousdownhill Does S2O82- react with Pb?

nonspontaneous- uphill Does Cu2+ react with Br-?

spontaneousdownhill Does Br2 react with Sn2+?

nonspontaneous- uphill Does Pb2+ react with Fe2+?

spontaneousdownhill Can you keep HCl in a Fe or a Ag container? HCl → H+ + Cl- Yes 2H+ + 2e- → H2(g) Fe → Fe2+ + 2e- No 2H+ + Fe → H2(g) + Fe2+

Can you keep HNO3 in a Au or a Ag container? Yes NO3- + 4H+ + 3e- → NO(g) + 2H2O Ag → Ag+ + e- x 3 No NO3- + 4H+ + 3Ag → NO(g) + 2H2O + 3Ag+