Unit 9 - Metals Flashcards
Reason for electrical conductivity in metals
Presence of delocalized electrons which can conduct electricity
Reason for thermal conductivity in metals
High density makes heat easier to pass through particles via vibrations
Reason for high melting and boiling points in metals
Strong forces of attraction need high temperatures to break bonds
Malleability
The ability to shape a substance
Ductility
The ability to pull a substance into stretched out wires
Reason for malleability and ductility in metals
Metals are arranged in layers with delocalized electrons that allow them to slide past each other easily
Reactions with metals and dilute acids
Metal + Acid –> Salt + Hydrogen
Reactions with metals and water
Metal + Water –> Metal hydroxide + Hydrogen
Reactions with metal and oxygen
Metal + Oxygen –> Metal oxide
Aluminum features
- Exceptionally low density but relatively strong
- Conducts electricity
- Corrosion resistant
Uses of aluminum
- Aircrafts - strong but low density
- Overhead cables - good conductor, low density
- Storing food - corrosion resistant
Uses of copper
- Wiring - high conductivity, very ductile, flexible
Alloys
Mixture of a metal and another element - tend to be stronger and harder than pure metals
Bronze composition
Tin and copper
Brass composition
Copper and zinc - causes it to be corrosion resistant and gold color
Steel composition
Group of alloys made with iron
Uses of steel
- Car engines
- Drill bits
- Cutting tools
Stainless steel composition
- Iron mixed with carbon and other metals e.g. chromium and nickel - protects rusting
Uses of stainless steel
- Cutlery
- Specialist equipment that process corrosive substances in chemical industry
Reasons for alloys’ lack of malleability and ductility
The admixture of particles of different sized causes the layers to not be able to slide/ interlocks them
Order of reactivity series
1.Potassium - K
2.Sodium - Na
3.Calcium - Ca
4.Magnesium - Mg
5.Aluminum - Al
6.Carbon - C
7.Zinc - Zn
8.Iron - Fe
9.Hydrogen - H
10.Copper - Cu
11.Silver - Ag
12.Gold - Au
Elements of the reactivity series and their reaction with water
- Aluminum and below don’t react
- Magnesium only reacts with steam
- Calcium reacts strongly
- Sodium reacts vigorously/violently
- Potassium reacts the most vigorous/violent
Elements of the reactivity series and their reactions with dilute HCl
- Magnesium - strong, forms bubbles quickly
- Zinc - bubbles form slowly
-Iron - Very slow, must be powdered iron - Rest don’t react
Displacement reaction
When a more reactive element takes the place of a less reactive element in a compound