3.5 - Metals Flashcards
what are the two components in the structure of a metal
- lattice of positive metal ions
- sea of delocalized electrons
what charges do metal ions in the metal structure have
their usual charge
what were the delocalized electrons lost by and how do they move
lost by the metal ions and they move freely through the lattice
what is metallic bonding
the electrostatic attraction between the positive metal ions and the negative delocalized electrons
what type of attraction is metallic bonding
usually very strong
what are the properties of metals
have high melting points
conduct electricity
malleable
why do metals tend to have high melting points
because the metallic bonding is very strong so lots of energy is needed to break it
why do metals conduct electricity
the delocalized electrons are free to move through the lattice
why are metals malleable
the layers of metal ions can slide over each other
what is thermal decomposition
a thermal decomposition reaction is when heat energy is used to break down a substance
what is the equation for a thermal decomposition
metal carbonate –> metal oxide + carbon doxide
what would the thermal decomposition of copper carbonate look like
copper carbonate –> copper oxide + carbon dioxide
CuCO3(s) CuO(s) CO2(g)
green solid black solid colourless gas
what is carbon dioxide often collected by in thermal decomposition
downward delivery
why is carbon dioxide collected by downward delivery
because carbon dioxide is denser than air
what is downward delivery
the carbon dioxide sinks to the bottom of a tube and stays there until you want to use it
list the metal reactivity series from lowest to highest
Au Ag Cu (H) Pb Fe Zn (C) Al Mg Ca Li Na K
why are hydrogen and carbon included in the reactivity series despite being non-metals
their positions are important when considering displacement reactions
what do metals react with cold water to form
metal hydroxides and hydrogen
what is the metal and water reaction equation
metal + water –> metal hydroxide + hydrogen
what are the two significant observations of metal and water reactions
effervescence - due to the hydrogen gas produced
solid disappears - due to being used up in the reaction
what are the metals in group 1 of the periodic table called
alkali metals
how do the metals in group 1 of the periodic table react with water
violently to form metal hydroxides and hydrogen
group 1 metal and water reaction equation
metal + water –> metal hydroxide + hydrogen
what similar observations do the reactions of Li, Na and K with water share
- solid floats - it is less dense than water
- effervescence - hydrogen gas is produced
- solid moves - the effervescence propels it around the surface of the water
- solid disappears - it is used up in the reaction
what happens when universal indicator is added to the water after its reaction with Li, Na or K
it turns dark blue - the metal hydroxides are alkalis because they donate OH-
what happens to the reaction of group 1 metals and water` as the reactivity increases
it gets more vigorous
what is the increasing reactivity order of Lithium, Sodium and Potassium
lithium (Li) , sodium (Na), potassium (K)
what are the extra observations of lithium reacting with water
fast
what are extra observations of sodium reacting with water
faster (than lithium)
Na melts
what are the extra observations of potassium reacting with water
fastest (out of it, sodium and lithium)
K melts
lilac flame
what happens to the group 1 metals as you go down the group
they get more reactive
what happens when a group 1 metal atom reacts
it loses its outer-shell electrons to get a full outer shell
why does losing outer shell electrons and getting a full shell happen more easily down the group of group 1 metals
- atoms get bigger and have more shells
- the outer-shell electron is further from the nucleus
- the attraction between the nucleus and the outer-electron is weaker
- so less energy is needed to break the attraction
what do metals react with steam to produce
metal oxide and hydrogen
metal reaction with steam equation
metal + steam –> metal oxide + hydrogen
what is a metal and steam reaction usually conducted in
a horizontal tube
in a metal and steam reaction what set up inside the horizontal tube
wet wool is heated to generate steam for the Mg to react with
the H2 gas product is ignited to safely destroy it
why do metals react with cold water and hot steam to produce different products
steam has more energy, so both bonds in the water molecule can break
what do acids react with metals to form
a salt and hydrogen gas
acid and metal reaction equation
acid + metal –> salt + hydrogen
what happens in an acid and metal reaction
a salt compound is formed when H is displaced from the acid
what salt does hydrochloric acid form
metal chloride (contains Cl-)
what salt does sulphuric acid form
metal sulphate (contains SO4 2-)
what salt does nitric acid form
metal nitrate (contains NO 3-)
what salt does phosphoric acid form
metal phosphate (contains PO4 3-)
is sodium (Na +) soluble
yes
is potassium (K +) soluble
yes
is ammonium (NH4 +) soluble
yes
is nitrate (NO3 -) soluble
yes
is chloride (Cl -)
yes - except with Ag + and Pb 2+
is sulphate (So4 2-) soluble
yes - except with Ca 2+, Ba 2+ and Pb 2+
is carbonate (CO3 2-) soluble
no - except with Na +, K+ and NH4 +
is hydroxide (OH -) soluble
no - except with Na +, K+ and Ca 2+
is oxide (O 2-) soluble
no - except with Na +, K+ and NH4 +)
what are the two important observations in an acid and metal reaction
the metal disappears
there is fizzing
why does the metal disappear in a metal and acid reaction
because it is used up in the reaction
why is there fizzing in a metal and acid reaction
because a gas (hydrogen) is produced
what happens to the reaction of a metal and an acid as the reactivity of a metal increases
the faster it reacts
which metals cannot react with acids and why
Au, Ag and Cu
it is not possible because they are less reactive than H so cannot displace it
which metals are not allowed to react with acids and why
Li, Na and K
reaction with acids is too violent
what is the chemical test for hydrogen
hydrogen in a test tube
lit splint -> squeaky pop
because the combustion of the hydrogen causes the test tube to resonate
what happens in displacement reactions
more reactive metals can displace less reactive metals from their compounds
what would the equation for the displacement of magnesium from copper from copper suphate
magnesium + copper sulphate –> copper + magnesium sulphate
Mg(s) + CuSO4(aq) –> Cu(s) + MgSO4(aq)
grey solid blue solution pink-orange colourless
solid solution
what are the two observations to always think about in metal displacement reactions
solid colour change
solution colour change
what happens to the non-metal part of the compound in a displacement reaction
remains unchanged
when can a displacement reaction occur
if the metal used is more reactive than the metal already in the compound
where are most metals found and what as
in the Earth’s crust as compounds with oxygen and sulphur
this is because over a long time those metals have reacted with oxygen and sulphur
what are ores
rocks containing specific metal compounds
what does native mean
chemically uncombined
which elements are too unreactive to combine with oxygen or sulphur
gold - Au
silver Ag
why don’t native metals need to be chemically extracted
they already exist on their own
what do metal ores need to be chemically extracted from
their compounds
what ways can metal ores be chemically extracted
1- using electricity
2- carbon extraction
what is using electricity for extraction of ores
metals more reactive than carbon cannot be displaced by carbon
instead we have to use electricity to break down their ore compounds
what is using carbon extraction for ores
metals less reactive than carbon can be displaced by carbon
what type of reaction is using carbon to displace a metal from its compound
a redox reaction
what is reduction
loss of oxygen
what is a reducing agent
takes oxygen away from something else
what is oxidation
gain of oxygen
what is oxidising agent
gives oxygen to something else
what is redox
reduction and oxidation in the same reaction
what is rusting
a chemical process by which iron is oxidised to form rust
what is the chemical name for rust
hydrated iron(III) oxide
what is the word equation for rust
iron –> iron(III) oxide –> hydrated iron(III) oxide
what is the chemical equation for rust
Fe(s) —> Fe2O3(s) —> Fe2O3.xH2O(s)
what are the properties of iron
grey
shiny
malleable
what are the properties of rust - hydrated iron(III) oxide
brown
dull
brittle
what two substances does rusting require
oxygen and water
how does rusting happen
1- iron is oxidized by oxygen to form iron(III) oxide
Fe has gained oxygen and it has also lost electrons to form Fe 3+ ions - it has been oxidized
2- iron(III) oxide is hydrated by water
what methods can prevent rusting
using barriers
sacrificial protection
galvanising
what is using barriers
coating the iron in paint, oil, grease or plastic prevents iron from coming into contact with oxygen or water
this only works as long as the coating is intact - as soon as it breaks rusting happens
what barrier would you use for a bike chain or for buckets
oil or grease for moving parts such as bike chains
paint or plastic for larger stationary objects such as buckets
what is sacrificial protection
attach a block of a more reactive metal to the iron
this works by displacing the iron from rust as soon as the rust forms
what is the downside to the sacrificial protection
the block such as block of magnesium has to be replaced often
what is galvanising
specifically involves coating the iron in zinc
why does galvanising work both ways
coating it prevents O2 and H2O from coming into contact with the iron
but even if a crack appears zinc is more reactive than iron so acts as sacrificial protection as well
what are alloys
mixtures of a metal with one or more other elements, usually other metals or carbon
list common alloys
steel
brass
bronze
elements in steel
iron + carbon
elements in brass
copper + zinc
elements in bronze
copper + tin
why are alloys harder than pure metals
because the different-sized atoms/ions prevent the layers of metal ions from sliding over each other which means the alloy is less malleable
what is the use of iron and why
making steel because it is more useful than iron
what is the use of low-carbon steel and why
ships, cars, bridges etc
because it is strong but carbon can also be hammered into many shapes
what is the use of high-carbon steel and why
tools - knives and screwdrivers
because high-carbon so less malleable and stiffer than low-carbon steel
what is the use of stainless steel and why
cutlery, cooking utensils, kitchen sinks
because Cr forms oxide layer that resists corrosion so stays shiny and clean
what is the use of copper and why
wires, cooking pans, water pipes
because excellent conductor of electricity, excellent conductor of heat, unreactive and malleable
what is the use of aluminiun and why
aircraft bodies, power cables
low-density and high strength, low-density and conducts
