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Home , Oxidizing agent, Reducing agent

Unit 7 :

15 Jan 2019 Agenda ● The Cycle of Copper Reactions ● Planning/paper sorting etc. ● Three Classes of reactions ○ Spontaneous redox ○ Electrochemical cells ○ and... ● Review naming systems

Oxidation of copper Oxidation Half reaction

Cu → Cu2+ + 2e- conc. is the

Precipitation of insoluble hydroxide - net ionic equation

2+ - Cu + 2 OH → Cu(OH)2(s)

Cu(OH)2 → CuO + H2O dehydration

CuO(s)+ H2SO4(aq) → CuSO4(aq) + H2O Acid-base reaction

Zn(s) + CuSO4(aq) → Cu(s) + ZnSO4(aq) Single displacement Zn → Zn2+ + 2 e- Oxidation

Cu2+ + 2e- → Cu Reduction Other Thermodynamically Favorable redox reactions?

Where substances come into contact and one gains electrons and the other loses electrons Other Thermodynamically Favorable redox reactions? Where substances come into contact and one gains electrons and the other loses electrons: (reaction with ) (including rusting of ) Reactive metals with water or acids Oxidation - loss of electrons - gets its name from combining with oxygen - now know an element does not need to combine with oxygen to be oxidized. Reduction- gaining electrons (from when metal ores were reduced to the metal which occupied a smaller volume). Charge reduced also. “LeO the lion says GeR” Oxidation - loss of electrons - gets its name from combining with oxygen - now know an element does not need to combine with oxygen to be oxidized. OXIDIZING agent - Reduction- gaining electrons (from when metal ores were reduced to the metal which occupied a smaller volume). Charge reduced also. - p.159 Reactions between metals and

2 Na (s) + Cl2(g) → 2 NaCl (s) Metal behaves as reducing agent (donates electrons) and itself is oxidized.

Nonmetal behaves as an oxidizing agent (accepts electrons) and is itself reduced.

Relative reducing powers of alkali metals can be predicted from... Reactions between metals and nonmetals

2 Na (s) + Cl2(g) → 2 NaCl (s) Metal behaves as reducing agent (donates electrons) and itself is oxidized.

Relative reducing powers of alkali metals can be predicted from first ionization energies

Expected trend in reducing ability Cs > Rb > K > Na > Li

(not observed when react in aq. solution Li > K > Na) p.318

Higher charge density on small Li+ ion affects hydration energy Reactions between metals and nonmetals

2 Na (s) + Cl2(g) → 2 NaCl (s) behaves as an oxidizing agent (accepts electrons) and is itself reduced.

Relative oxidizing powers of is such a powerful oxidising agent that you can't reasonably do solution reactions with it. https://www.chemguide.co.uk/inorganic/group7/halogensasoas.html Different metals have different tendencies to lose electrons (be oxidized)

Mg (s) + 2 HCl(aq) → MgCl2(aq) + H2(g) Thermodynamically favorable ΔH negative, exothermic

ΔS positive - gas produced overall ΔG negative

Cu (s) + 2 HCl(aq) → no reaction

Ag (s) + 2 HCl(aq) → no reaction Different metals have different tendencies to lose electrons (be oxidized) What is likely to be going on here?

Cu (s) + 2AgNO3 (aq) → no reaction Different metals have different tendencies to lose electrons (be oxidized)

Cu(s) + 2AgNO3 (aq) → Ag(s) + Cu(NO3)2(aq) Combining

Data from lots reactions

We generate

A for metals.

(Most reactive, most likely to donate electron and be oxidized, strongest reducing agents.) Spud-u-like labette 1. Insert 4 metal strips (, copper, magnesium and ) into a potato. 2. Use a voltmeter to measure the voltage between all possible combinations of two of the metals. 3. Generate a complete results table for all the possible combinations. 4. Order the metals from the most likely to be oxidized to least likely to be oxidized - with justifications from evidence. ____V

1.30V 0.86 V Homework: Review naming systems. (Quiz on naming systems next week).

Figure 2.23 A flowchart for naming binary compounds

Figure 2.24 Overall strategy for naming chemical compounds

Table 2.7 Names of Acids that do not contain oxygen

Table 2.8 Names of some oxygen containing acids