What do you know about the second volume of Chemistry for Grade 9 "Metals and Metallic Materials"?

Unit 8 Metal Materials Knowledge Points

1. Metal Materials

Pure metals (more than 90 types)

Alloys (several Thousands of species)

2. Physical properties of metals: (1) Generally solid at room temperature (mercury is liquid), with metallic luster.

(2) Most of them are silvery white (copper is purple, gold is yellow)

(3) It has good thermal conductivity, electrical conductivity and ductility

3. The most abundant metal:

(1) Aluminum: The most abundant metal element in the earth’s crust

(2) Calcium: The most abundant metal element in the human body

(3) Iron: The metal with the largest annual output in the world (iron>aluminum>copper)

(4) Silver: the metal with the best electrical and thermal conductivity (silver>copper>gold> Aluminum)

(5) Chromium: The metal with the highest hardness

(6) Tungsten: The metal with the highest melting point

(7) Mercury: The metal with the lowest melting point

(8) Osmium: The metal with the highest density

(9) Lithium: The metal with the smallest density

4. Metal classification:

Ferrous metal: usually refers to iron, manganese, chromium and their alloys.

Heavy metals: such as copper, zinc, lead, etc.

Non-ferrous metals

Light metals: such as sodium, magnesium, aluminum, etc.;

Non-ferrous metals Metal: Usually refers to metals other than ferrous metals.

5. Alloy: A substance with metallic properties formed by the fusion of one metal and one or several other metals (or metals and non-metals).

★: Generally speaking, the melting point of the alloy is lower than that of the components, the hardness is greater than the components, and the corrosion resistance is better

Alloy iron, copper alloy solder, titanium and titanium alloy Shape memory metal

Pig iron steel brass bronze:

Composition carbon content

2%~4.3% carbon content

0.03 %~2% copper-zinc

Alloy copper-tin

Alloy lead-tin

Alloy titanium-nickel alloy

Remarks Stainless steel: containing chromium, Nickel-based steel

It has corrosion resistance. Red copper has a low melting point as pure copper

Note: Titanium and titanium alloys are considered important metal materials in the 21st century. Titanium alloys have a close relationship with the human body. Good "compatibility", so it can be used to make artificial bones, etc.

(1) High melting point, low density

Advantages (2) Good plasticity, easy processing, good mechanical properties

(3) Good corrosion resistance< /p>

2. Chemical properties of metals

1. Most metals can react with oxygen

2. Metal + acid → salt + H2↑

3. Metal + salt → another metal + another salt (condition: "replacement of front and back, salt is soluble")

Fe + CuSO4 == Cu + FeSO4 ("hydrometallurgy" Principle)

3. Common metal activity sequence:

K Ca Na Mg Al Zn Fe Sn Pb (H) Cu Hg Ag Pt Au

Metal activity The activity gradually weakens from strong to strong

In the order of metal activity:

(1) The higher the position of the metal, the stronger its activity

(2) The metal in front of the hydrogen can displace the hydrogen in hydrochloric acid and dilute sulfuric acid (concentrated sulfuric acid and nitric acid cannot be used)

(3) The metal in front can remove the metal in the back from their salts displaced from the solution. (Except K, Ca, Na, Ba)

IV. Protection and utilization of metal resources

1. Smelting of iron

(1) Principle: At high temperatures, carbon monoxide generated by the reaction of coke and oxygen is used to reduce iron from iron ore.

3CO + Fe2O3 high temperature 2Fe + 3CO2

(2) Raw materials: iron ore, coke, limestone, air

Common iron ores include magnets Ore (the main component is Fe3O4), hematite (the main component is Fe2O3)

2. Iron rust

(1) The conditions for iron to rust are: iron and O2, Water contact (main component of rust: Fe2O3)

(Conditions for copper to develop patina: Copper is in contact with O2, water, and CO2.

The chemical formula of patina: Cu2(OH)2CO3)

(2) Measures to prevent iron products from rusting:

①Keep the surface of iron products clean and dry

②Surface coating with protective film: such as oiling, painting, electroplating, blue baking, etc.

③Made into stainless steel

Rust is very loose and cannot prevent the iron in the inner layer from continuing to interact with oxygen , water vapor reaction, so all iron products can be rusted. Therefore, rust should be removed in time.

Aluminum reacts with oxygen to form a dense aluminum oxide film, which prevents further oxidation of aluminum. Therefore, aluminum has good corrosion resistance.

3. Protection and utilization of metal resources:

Ways to protect metal resources:

①Prevent metal corrosion

②Recycling Scrap metal

③Rational mining of minerals

④Looking for metal substitutes

Meaning: Save metal resources and reduce environmental pollution