Chemistry In Industry Flashcards
How are most metals found?
in their ores
in the Earth’s crust combined with other elecments
the individual compounds are called minerals
What is a metal ore?
a metal ore is a compound that contains enough the mineral for it to be economically viable to extract some metal
What is the price of a metal affected by>
how common the ore is
how difficult it is so extract the metal from its ore
There is a limited/unlimited amount of metal ores - they are … resources
There is a limited amount of metal ores - they are finite resources
The more reactive a metal is, the easier/harder it is to extract it from its compound
The more reactive a metal is, the harder it is to extract it from its compound
What are native metals?
very unreactive metals, such as godl, that exist naturally as the uncombined element (you just have to find them and dig them up)
silver and copper are also sometimes found native - although much more rarely
What do metals often have to be separated from?
their oxides
How to metals form oxides?
lots of metalls, like iron and aluminium, react with oxygen to form oxides
these oxides are often the ores that the metals need to be extracted from
What is the name of the reaction that separates a metal from the oxygen it its oxide?
a reduction reaction
e.g. 2CuO + C → 2Cu + CO2
The most common type of reduction reaction uses … as a reducing agent to separate the oxygen from the metal
The most common type of reduction reaction uses carbon as a reducing agent to separate the oxygen from the metal
Metals exist as positive ions in their …. To produce the metal you would have to …. This is called …
Metals exist as positive ions in their ionic compounds. To produce the metal you would have to add electrons to the positive ion. This is called called reduction
What is ‘roasting’?
converting a metal compound into an oxide by heating in air
What are the two main economic factors to take into account when deciding on the method of reducing an ore to the metal?
the cost of energy
the cost of the reducing agent
How are some metals, such as titanium, extracted? Is this expensive? Why?
by heating thecompound with a more reactive metal
this is expensive, because the more reactive metal itself will have to be extractedby an expensive process first
How are metals below carbon in the reactivity series extracted? Is this expensive? Why?
they are extracted by a reduction reaction by heating the metal ore with carbon or carbon monoxide
this is the cheapest method of reducing the ore
carbon is cheap and can also be used as the source of heat
What is the order of the reactivity series?
potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
tin
lead
hydrogen
copper
silver
gold
platinum
How do you remember the order of the reactivity series?
polly
smith
cut
my
amazingly
cool
zebra
into
two
lamp
hamburger
chops
creating
super
gravy
platas
Explain how are metals below carbon in the reactivity series are extracted by heating the ore with carbon or carbon monoxide
more reactive elements form compounds more readily
carbon is more reactive than, for example, iron, so carbon displaces the oxygen from iron oxide
carbon can only remove the oxygen away from metals which are less reactive than carbon itself
Ores of metals higher in the reactivity series than zinc can’t be reduced using carbon at …
Ores of metals higher in the reactivity series than zinc can’t be reduced using carbon at reasonable temperatures
How are metals above carbon in the reactivity series extracted? Is this expensive?
by electrolysis
the large amounts of electricity involved make this an expensive process so a metal like aluminium is much more expensive than one like iron
Very reactive metals form very stable/unstable ores - it’s easy/difficult to get the metal out of its compound
Very reactive metals form very stable ores - it’s difficult to get the metal out of its compound
What can burning fuels produce? Give three examples
pollutants
e.g. carbon monoxide, nitrogen oxides and sulphur dioxide
How is carbon monoxide (CO) produced?
when hydrocarbon fuels (e.g. petrol or diesel in car engines, or gas in central heating) are burnt without enough oxygen - incomplete combustion
Why is carbon monoxide poisonous? What can this lead to?
it can stop your blood cells doing their proper job of carrying oxygen around the body as it combines with the haemoglobin in blood cells, meaning the blood can carry less oxygen
a lack of oxygen in the blood can lead to fainting, a coma or even death
When are sulphur dioxide (SO2) and nitrogen oxides released?
when fossil fuels are burned
How is sulphur dioxide formed?
sulphur impurities in fossil fuels
How are nitrogen oxides formed?
when the temperature is high enough for the nitrogen and oxyegn in the air to react
this often happens in car engines
What are two examples of nitrogen oxides?
nitrogen monoxide (NO) nitrogen dioxide (NO<sub>2</sub>)
All rain is … acidic because …
All rain is slightly acidic because carbon dioxide in the air reacts with water to produce a slightly acidic solution:
carbon dioxide + water → carbonic acid
CO2 (g) + H2O (l) → H2CO3 (aq)
What happens when sulphur dioxide mixes with clouds?
when sulphur dioxide mixes with clouds it forms dilute sulphuric acid, which is much more acidic:
sulphir dioxide + oxygen +water → sulphuric acid
2SO2 (g) + O2 (g) + 2H2O (l) → 2H2SO4 (aq)
What can nitrogen oxides form in clouds?
nitric acid
What is acid rain caused by?
sulphur dioxide and nitrogen oxides mixing with clouds
rain that falls from these clouds is called acid rain
What does acid rain do to lakes?
acid rain causes lakes to become acidic and many plants and animals die as a result
What does acid rain do to trees?
acid rain kills trees
What does acid rain do to buildings and statues?
acid rain can damage limestone buildings and ruins stone statues
