C10 - Metals Flashcards
Describe metallic bonding [2]
Lattice of positive metal ions in a sea of delocalised electrons
Describe general physical properties of metals [4]
High melting and boiling points, malleable, ductile, good conductors of heat and electricity
Define malleable [1]
Can be bent of hammered into shape
Define ductile [1]
Can be drawn into wires
Define an alloy [1]
A mixture of a metal with another substance
Explain why an alloy is more useful than the pure metal [3]
It is harder (more difficult to scratch) because the other element disrupts the lattice structure and makes it more difficult to remove the layers from the metal
What is brass [1]
An alloy of copper and zinc
What do we call an alloy that contains iron and other substances? [1]
Steel
Why is nickel and chromium alloyed with iron? [2]
Chromium prevents steel from rusting, nickel makes it harder
Place in order of reactivity the following elements: Al, C, Ca, Cu, Fe, H₂, K, Mg, Na, Zn [1]
K, Na, Ca, Mg, Al, C, Zn, Fe, H₂, Cu
How does the reactivity of a metal relate to how easy it is to extract from its ore? [1]
The more reactive a metal is the more difficult it is to extract from its ore
How does the reactivity of a metal relate to its tendency to form a positive ion? [1]
The more reactive a metal the easier it is to lose its valence electron(s) and form a positive ion
Write a symbol equation for the reaction between magnesium and hydrochloric acid [1]
Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂ (g)
Write a symbol equation for the reaction between magnesium and oxygen [1]
2Mg (s) + O₂ (g) → MgO (s)
Write a symbol equation for the reaction between sodium and cold water [1]
2Na (s) + 2H₂O (l) → 2NaOH (aq) + H₂O (g)
Write a symbol equation for the reaction between magnesium and steam [1]
Mg (s) + 2H₂O (g) → MgO (s) + H₂ (g)
Define an ore [1]
A rock that contains a high enough percentage of metal for economic extraction
Why is it important that metals are recycled?
Because metal ores are finite
How are elements above carbon in the reactivity series extracted from their ores? [1]
Electrolysis
How is iron extracted from the metal ore haematite in the blast furnace [1]
By heating with carbon
Write 3 symbol equations to show how carbon is used to extract iron from haematite [3]
C + O₂ → CO₂ C + CO₂ → 2CO Fe₂O₃ + 3CO → 2Fe + 3CO₂
Explain whith the use of 2 symbol equations why limestone (CaCO₃) is used in the blast furnace [3]
To remove acidic impurities such as silicon (IV) oxide CaCO₃ → CaO + CO₂ CaO + SiO₂ → CaSiO₃
Explain 2 uses of aluminium [4]
Aircraft because of its strength and low density and in food containers because of its resistance to corrosion
Describe the uses of mild steel and stainless steel [2]
Mild steel for car bodies and machinery and stainless steel for chemical plants and cutlery
Describe and explain the apparent unreactivity of aluminium [2]
Aluminium forms an oxide layer which protects the metal underneath
Explain why zinc is used for galvanising steel [2]
As a more reactive metal zinc provides sacrificial protection, this means is reacts before the metal underneath
