1. Combustion

2. Hydrocarbons
Ethyne (acetylene)
C2H2
Methane
CH4
Butane
C4H10

3. Complete Combustion
Occurs when there is plentiful O2 gas Produces ONLY CO2 (g) and H2O(g) Note: not liquid water CxHy + O2 (g)  CO2 (g) + H2O(g) Lots of oxygen, fuel-lean

4. Complete combustion of ethyne C2H2 (g) + O2 (g) 

5. Complete combustion of ethyne C2H2 (g) + O2 (g)  CO2 (g) + H2O(g) Balancing tip: C, then O, then H

6. Complete combustion of ethyne 2 C2H2 (g) + 5 O2 (g)  4 CO2 (g) + 2 H2O(g) Balancing tip: C, then O, then H

7. What if oxygen is limited? C2H2 (g) + 3 O2 (g) 

8. What if oxygen is limited? C2H2 (g) + 3 O2 (g)  CO2 (g) + H2O(g)

9. What if oxygen is limited
What if oxygen is limited? C2H2 (g) + 3 O2 (g)  CO2 (g) + H2O(g) Can’t balance!

10. Incomplete Combustion
Occurs when there is not enough O2 gas Produces C(s) CO(g) CO2 (g) and H2O(g) CxHy + O2 (g)  C(s) + CO(g) + CO2 (g) + H2O(g) Not enough oxygen, fuel-rich

11. Properties of products
H2O(g)
C and IC combustion
Cobalt chloride paper turns from blue to pink
CO2 (g)
Limewater cloudy

12. Properties of products
C(s)
IC combustion only
Solid carbon-rich molecules (“soot”)
Inhalation hazard
CO(g)
C and IC combustion only
Toxic gas – silent killer

13. Combustion Complete Incomplete Blue flame No residue Hotter
Uses all energy available
Yellow flame
Sooty residue
Colder
Wastes energy
Toxic gas produced
Inhalation hazard
Lights faster

14. Review

15. Quiz
Zinc is added to a solution of copper nitrate. Barium nitrate and potassium carbonate are mixed. When current passes through water, two gases are formed. Sulfuric acid, H2SO4 (aq) is dropped onto steel wool.

16. Potassium sulfate and iron (III) chloride are mixed
Potassium sulfate and iron (III) chloride are mixed. Sodium metal is placed in a flask containing fluorine gas. Nickel (II) sulfite in aqueous solution is mixed with hydrofluoric acid.

17. Quiz
Copper is added to a solution of zinc nitrate. Cu(s) + Zn(NO3)2(aq)  NR NR Barium iodide and potassium carbonate are mixed. BaI2(aq) + K2CO3(aq)  BaCO3(s) + 2 KI(aq) DD When current passes through water, two gases are formed. 2 H2O(l)  O2(g) + 2 H2(g) D Sulfuric acid, H2SO4 (aq) is dropped onto steel wool. Fe(s) + H2SO4(aq)  FeSO4(aq) + H2(g) SD

18. Potassium sulfate and iron (III) chloride are mixed
Potassium sulfate and iron (III) chloride are mixed. K2SO4(aq) + FeCl3(aq)  NR NR Sodium metal is placed in a flask containing fluorine gas. 2 Na(s) + F2(g)  2 NaF(s) S Nickel (II) sulfite in aqueous solution is mixed with hydrofluoric acid. NiSO3(aq) + 2 HF (aq)  NiF2(aq) + H2O (l) + SO2 (g) DD, D

19. Chapter Review
Chapter 4 Review #39-80 except 47,53 Pick and choose Chapter 5 Review #35-39, 43, 54, 57, 59, 63, 76

20. Homework Unit summary sheet for test Be prepared for Monday Read 5.1