Chemical Reactions and Processes: A Concise Summary
Chapter 1: Flame Tests
Flame Test Colors:
- Calcium: Red
- Copper: Blue/Green
- Potassium: Purple
- Sodium: Orange
Displacement Reaction: A more reactive metal displaces a less reactive metal from its salt solution.
Chapter 2: Iron Extraction and Alloys
Blast Furnace: A large piece of equipment used to extract iron from its ore using a reduction reaction.
Process:
- Iron ore, limestone, and coke are added.
- Air is blown in.
- Carbon + Oxygen → Carbon Dioxide + Heat
- Carbon Dioxide + Carbon → Carbon Monoxide
- Iron Oxide + Carbon Monoxide → Iron + Carbon Dioxide
Electrolysis: Passing electricity through molten aluminum ore to collect pure liquid aluminum.
Alloy: A substance made up of a mixture, mainly of metals.
Steel: An alloy of iron with controlled amounts of carbon and other elements. It is stronger than iron, less brittle, and more resistant to rusting.
Uses of Steel:
- Mild steel (less than 0.15% carbon): Car bodies
- Stainless steel (high chromium content): Cutlery
Aluminum:
| Properties | Uses |
|---|---|
| Resistant to corrosion | Food containers |
| Low density | Airframes of airplanes |
| Good electrical conductor | Overhead electrical cables |
Chapter 3: Reaction Rates
Rate of Reaction: How fast a reaction proceeds.
Measured by:
- Appearance of product
- Disappearance of reactants
Factors Affecting Rate of Reaction:
- Temperature
- Concentration of solutions
- Surface area of solid reactants
- Presence or absence of a catalyst
Controlled Conditions:
- Temperature of solution
- Concentration of solution
- Volume of solution
- Mass of solid
- Surface area of solid
A catalyst increases the rate of reaction. More catalyst results in a faster reaction rate.
Catalysts in Industry: Speed up chemical processes, allowing them to happen faster and at lower temperatures, saving companies money.
Chapter 5: Ion and Gas Tests
Tests for Ions:
- Carbonate (CO32-): Bubbles with acid.
- Chloride (Cl–): Silver nitrate produces a white precipitate.
- Nitrate (NO3–): Aluminum foil produces ammonia.
- Sulfate (SO42-): Barium (something) produces a white precipitate.
Tests for Cations:
- Ammonium (NH4+): Ammonia produced, turning litmus paper blue.
- Copper(II) (Cu2+): Blue precipitate, then dark blue solution.
- Iron(II) (Fe2+): Green precipitate, insoluble in excess.
- Iron(III) (Fe3+): Red-brown precipitate, insoluble in excess.
- Zinc (Zn2+): White precipitate, then colorless solution.
Chapter 6: Electrolysis
Electrode: Metal rods placed in the liquid through which electricity passes.
Anode: Positive electrode.
Cathode: Negative electrode.
Electrolyte: Solution of an ionic substance through which electrical current passes.
Electrolysis: Breaking down of a compound in the electrolyte using direct electric current.
Example: Electrolysis of Aqueous Copper(II) Chloride
| Electrodes | Electrolyte | Anode | Cathode |
|---|---|---|---|
| Carbon | Aqueous Copper(II) Chloride | Bubbles of chlorine gas (green) | Electrode coated with copper (red) |
Process:
- Positive copper ions are attracted to the cathode, pick up electrons, and become copper metal.
- Negative chloride ions are attracted to the anode, lose electrons, and become chlorine gas.
Chapter 7: Thermal Decomposition and Combustion
Thermal Decomposition: Breaking down of complex substances into simpler ones using heat (no oxygen needed).
Combustion: A chemical reaction between a fuel and oxygen that produces heat (the process of burning).