Metals Flashcards
Why do we use copper pipes
Copper doesn’t react with water
Why can a more reactive metal displace a less reactive metal from its salt
As it forms positive ions more easily, the higher up on the reactivity series the more reactive
What metal is used in sacrificial protection
Zinc
Why are carbon and hydrogen apart of the reactivity series
They are used to extract metal from their oxides
What is a measure of how reactive the metal is
The tendency of the metal to lose electrons to form a positive ion
When does a displacement reaction occur
When a more reactive metal can displace a less reactive metal ion from its salt
Physical properties of metals (3)
Good conductors of heat + electricity
Malleable+ductile
High melting and boiling point
Physical properties of metalloids
A mix between metals and non-metals
Physical properties of non metals(3)
Do not conduct heat or electricity
Low melting and boiling point
Brittle
4 reactions with metals
Cold water
Steam
Oxygen
Acid
Reaction of metal with acid
Metal + acid -> Metal salt + hydrogen
Forms metal salt and hydrogen gas
Reaction of metal and cold water
Metal + water -> metal hydroxide + hydrogen
Forms metal hydroxide and hydrogen gas
Reaction of metal and steam
Forms metal oxide and hydrogen gas
Metal + steam -> metal oxide + hydrogen
Reaction of metal and oxygen
Some reactive metals (alkali) react easily, unreactive metals don’t at all
Metal + oxygen -> metal oxide
Alloy and advantages of alloys
Mixture of a metal with other elements
Tend to be harder, stronger and more resistive to corrosion and high temperatures
Uses of aluminium and the properties most suitable for that use (5)
Aeroplane bodies - high strength to weight ratio and low density
Tin cans - non-toxic, resistant to corrosion and acidic food
Saucepans - good conductor of heat
Window frames - resistant to corrosion
Overhead power cables - good conductor of electricity and low density
In what form/state will the salt be after a metal reacts with acid
Aqueous
What are the uses of copper (3) and why
Electrical wires - good conductor of electricity, malleable and ductile
Water pipes - easy to work with and bend non-toxic and unreactive (does not react with water)
Cooking pans - malleable, unreactive to water and good conductor of heat
Alloy
Mixture of a metal with other elements
Advantages of alloys
Harder
Stronger
More resistive to corrosion/high temperatures
3 commonly used alloys, and their mixture composition
Brass - copper and zinc
Stainless steel - Iron and other elements usually nickel/carbon/chromium
Aluminium alloy - aluminium + silicon +manganese
What does it mean if theres a white shine in stainless steel
It is an alloy containing chromium
Uses of 3 alloys and why
Brass - jewelery, musical instruments (corrosion resistant and has conductive properties)
Stainless steel - cutlery (hardness and resistance to rust)
Aluminium alloy - aircraft bodies (alloy is stronger but still has a low density)
Why are alloys harder than most pure metals
Alloys contain atoms of different sizes which distorts the normally regular arrangement of atoms in metals making it more difficult for the layers to slide over each other. This means what alloys are harder than most pure metals
How can we determine the reactivity of a metal
Reacting metals with water and acids.
The more vigorous the reaction the higher up on the reactivity series
The greater the change in temperature, the higher up on the series
List the reactivity series
Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Hydrogen
Copper
Silver
Gold
Displacement reactions
When a more reactive metal can displace a less reactive metal ion from its salt
The higher up on the RS , the easier it is to lose electrons (forms cation)
Reactivity of aluminium
Does not react with water, only slowly reacts with dilute acids. Reacts readily with oxygen forming a protective, thin layer of aluminium oxide. This prevents reaction with water and dilute acids allowing aluminium to behave as if it is an unreactive metal
Thermal decomposition of metal compounds formulas (4)
Metal hydroxides -> mtetal oxide + water
Metal carbonates -> metal oxide +carbon dioxide
Metal nitrates -> metal oxide +nitrogen dioxide + oxygen
Group 1 metal nitrates -> metal nitrite + oxygen
Colour of oxygen gas
Colourless
Colour of nitrogn dioxide gas
Reddish-brownish
Thermal stability of group 1 carbonates
Carbonates are more thermally stable than group 2, so the compounds must be heated to undergo decomposition (needs more heat to break down)
Rust
(Statements and formula)
ONLY HAPPENS WITH IRON
Chemical reaction between iron, water and oxygen to form the compound hydrated iron (III) oxide
Oxygen and water must be present for reaction to occur
Iron is oxidised (loses some of its electrons)
Methods of rust prevention (2)
Barriers
Galvanising
Galvanising
Eg.
Process where iron is coated witgh a layer of zinc. As zinc is more reactive than iron it loses its electrons more easily/is more easily oxidised. It corrodes first and protects the less reactive metal from corrosion
Zinc bars on the side of ships
Sacrificial protection
A more reactive metal can be attached to a less reactive metal, the more reactive metal will oxidise and corrode first and protect the less reactive metal from corrosion
Eg. Zinc bars on sides of steel ships
Barrier - rust prevention
Common methods (4)
Cover iron with barriers that prevent it from coming into contact with water and oxygen
If coatings are scratched/washed away the iron is exposed again
Oil, paint, plastic, grease
Describe the reaction of:
Potassium
Sodium
Calcium
With water
Potassium: vigourously (exothermic) to form a colourless, basic, KOH solution
Sodium: readily (exothermic) to form NaOH and H gas
Calcium: less strongly to form CaOH and H
Reaction of magnesium with steam
Burns in steam to produce white magnesium oxide and hydrogen gas
