Tiêu đề EDX Topic 10.pdf ✅

Topic 10 Metals 1

3 Metal Use Properties Copper Electric Wires Ductile & Good Conductor of Electricity Saucepans Malleable & Good Conductor of Heat Water Pipes Malleable & Doesn’t react with water Hospital Tops Anti-microbial properties & malleable Alloys An Alloy is a mixture of a metal with other elements to have better properties Why do we make alloys? Alloys are harder & stronger Some alloys are more resistant to corrosion Examples Alloy Composition Properties Uses Stainless Steel Iron + Copper + Chromium + Nickel Harder than pure iron resistant to corrosion Cutlery, Kitchen, Sinks High Carbon Steel Iron + 0.5 - 1.5% Carbon Harder than pure iron and mild steel Railway lines, drills Mild Steel Iron + 0.25% Carbon Harder than pure iron Car bodies, Machinery Topic 10
4 Pure Metals are Malleable? Alloys are harder and stronger than pure metals? Explain Why? Because metal atoms are regularly arranged in layers. The layers can slide over each other Because alloys have different sized atoms which disrupts the movement of particles so the layers can no longer slide over each other Rusting of Iron Rusting of Iron Corrosion is the gradual destruction due to chemical reaction with its surroundings Corrosion of Iron and steel has a special name: Rusting What’s Rusting? It is a chemical reaction between Iron & Oxygen in presence of water forming reddish brown layer on the surface of Iron called hydrated Iron (III) Oxide The Iron object gains weight after rusting What are the causes of rusting? The presence of BOTH Oxygen & Water. What are the factors that speed up rusting? Acids Salts High Temperature Topic 10