metals Flashcards
describe the structure of a metal
- lattice of positive ions
- sea of delocalised electrons
define metallic bonding
the electrostatic attraction between the positive metal ions and the negative delocalised electrons
is metallic bonding a strong or weak attraction
very strong
what is thermal decomposition
a thermal decomposition reaction is when heat energy is used to break down a substance
what do metal carbonates decompose into
metal oxides and carbon dioxide
metal carbonate -> metal oxide + carbon dioxide
what occurs when copper carbonate is thermally decomposed
turns from green to black and releases co2
what is downward delivery
- carbon dioxide is denser than air so its often collected by downward delivery
- this means it sinks to the bottom of the tube
-and it stays there until you need to use it
what are the properties of metals
- high melting and boiling point
- conduct electricity
- malleable
list the metal reactivity series from low to high
- Au (lowest)
- Ag
- Cu
- H
- Pb
- Fe (middle)
- Zn
- C
- Al
- Mg
- Ca
- Li
- Na
- K (highest)
give the metal + water equation
- metals react with cold water to form metal hydroxides and hydrogen
- metal + water -> metal hydroxide + hydrogen
observations of metal + water reactions
- effervescence: due to the hydrogen gas produced
- solod disappears: due to being used up in the reaction
what are the metals in group 1 called and how do they react in water
- alkali metals
- they react violently in water
what are the reactions of Li and K in water
- solid floats: it is less dense than water
- effervescence: hydrogen gas is produced
- solid moves: it is propelled by the effervescence across the surface
- solid disappears: it is used up in the reaction
what is the group 1 reactivity series
Li
na
k
rb
cs
- the group 1 metals get more reactive as you go down the group
why do group 1 metals get more reactive as you go down the group
when a group 1 metal reacts it loses its outer shell electron to get a full outer shell, this happens more easily as you down the group because:
- the atoms get bigger and have more shells
- the outer electron is further from the nucleus
- the attraction between the nucleus and the outer electron is weaker
what is the equation for the metal + steam reactions
metal + steam -> metal oxide + hydrogn
where does the metal+steam reaction take place
horizontal tube
what is the method for reacting magnesium and steam
- mg + h2o -> mgO + H2
- wet wool is heated to generate steam for the mg to react with
- the h2 gas produced is ignited safely to destroy it
why do metals react with cold water and steam to produce different products ?
steam gas more energy so bith bonds in the water molecule can break
what is the acid + metal equation
acid + metal -> salt + hydrogen
what are the observations of an acid + metal reaction
- effervescence: because hydrogen gas is produced
- the metal disappears: because its used up in the reaction
what is a displacement reaction
more reactive metals can displace less reactive metals from their compounds
observations of a displacement reaction
- solid colour change
- solution colour change
what is an ore
metals found in the earths crust as compounds of oxygen and sulphur. this is because over a long time those metals have reacted with oxygen and sulphur.
how do you extract ores
metals in ores need to be chemically extracted from their compounds.
how this is done depends on their reactivity
how are native metals extracted
native metals dont need to be chemically extracted because they exist on their own
how are metals extracted using electricity
- metals more reactive than carbon cannot be extracted by carbon
- electricity is used to break down their ore compounds
how are metals extracted from their ores using carbon extraction
- metals less reactive than carbon can be displaced by carbon
what is the definition of rusting
a chemical process by which iron is oxidised to form rust
what is the chemical name for rust
hydrated iron(III) oxide
what does rust require to occur
- oxygen
- water
how can rust be prevented
1)using barriers:
- paint
- oil
- grease
- plastic
2)sacrificial protection
-adding a block of more reactive metal e.g magnesium, this works by displacement
3) galvanising
-coating the iron in zinc
what is the definition of an alloy
a mixture of a metal and one or more other elements, usually other metals or carbon
what are an alloys characteristics
- harder than pure metals
- because the different sized atoms/ions prevent then sliding over each other
- this means its less malleable
how is the alloy iron used in real life
making steel
how is the alloy low-carbon steel used in real life
ships, cars, bridges etc
how is the alloy high-carbon steel used in real life
tools e.g screwdriver or knife
how is the alloy stainless steel used in real life
cutlery, cooking utensils, kitchen sinks
how is the alloy copper used in real life
wires, cooking pans, water pipes
how is the alloy aluminium used in real life
aircraft bodies, power cables
