chem - metals Flashcards
what is the main use for iron and why?
in construction as it is strong and cheap
what is the main use for aluminium and why,
pilon wires - as it has a good conductor of electricity, and a low density
what does aluminium bring a good conductor of heat mean it can be used to make?
can make saucepans
why is aluminium also a good material to make saucepans
doesn’t react with food cause of protective layer of aluminium oxide on surface - layer means u can also make window frames with it due to lack of corrosion
what 3 things is copper used for and why (2 different reasons)
electrical wires - excellent conductor
hot water pipes and boilers - unreactive
why are gold and copper used to make jewellery?
unreactive and have an attractive appearance - im comparison to metals that are dull or who react and lose their shine
metals are used in construction because of what property?
they’re strong
metals are used in car body panels (made out of sheet steel) because of what property?
they’re malleable
metals are used in the moving part of engines because of what property?
they’re strong
metals are used in electrical wiring because of what property?
they are ductile and excellent conductors of electricity
metals are used as heat sinks to cool microprocessors and stop them overheating because of what property?
they are good conductors of heat
what happens to copper when it burns (in oxygen)
turns black slowly - as it is covered with a layer of black copper oxide
what happens to magnesium when it burns (in oxygen)
a white solid is formed (MgO), and it burns with a bright WHITE flame
what happens to calcium when it burns (in oxygen)
white solid formed -(CaO), burns with a bright RED flame
what happens to zinc powder when it burns (in oxygen)
white ZnO is formed, and it burns with a BLUEISH flame
what happens to iron filings when it burns (in oxygen)
brown solid - Fe2O3 is formed, and they burn with a YELLOW/ORANGE flame
what happens to potassium when it burns (in oxygen)
a white solid - K2O is formed, burns with a LILAC flame
what happens to copper when it is reacted with hydrochloric acid
no reaction
what happens to magnesium when it is reacted with hydrochloric acid
gets warm and there’s effervescence
what happens to calcium when it is reacted with hydrochloric acid (3 things)
smoking, heat and effervescence
zinc had no reaction but iron did (there were some bubbles) - yet zinc is more reactive - why is this?
because it was powdered iron so greater SA : Vol ratio and more collisions, so if it had been powdered zinc it would have reacted more strongly
what happens to potassium when it is reacted with hydrochloric acid
explosive reaction
How do tin, lead and copper react with oxygen?
react slowly - forming a layer of oxide
how do silver, gold and platinum react with oxygen?
they don’t react
Magnesium is different from other alkali/alkaline earth metals - potassium, sodium, lithium and calcium - when it reacts with water/ steam, how is it different
they all react fast with water, (less vigorous as you move down), however magnesium reacts slowly with cold water and only fast with steam
which metals don’t react with water or steam?
tin, lead, copper, silver, gold and platinum
which metals react with steam but not with water?
aluminium, zinc and iron
which metals DO NOT react with dilute acids?
copper, silver, gold and platinum
which metals react with acids to give hydrogen gas?
calcium, magnesium, Aluminium, zinc and iron
? and lead have very ? reactions with acids
tin, slow
potassium, sodium and lithium all have a violent explosive reaction when reacted with acid - true or false?
true
what are displacement reactions?
reactions in which a more reactive will take the place of a less reactive one
what happens in a reaction between magnesium and copper (2) sulphate and why?
there is a reaction - the solution turns green - this happens as magnesium is more reactive than copper (2) sulphate so it displaces it and turns into magnesium sulphate and copper
what is order of reactivity with copper, iron, magnesium and zinc (most to least)
magnesium, zinc, iron and copper
what are the two definitions of oxidation?
loss of electrons and the gain of oxygen (combining with oxygen)
what are the two definitions of reduction?
again of electrons, loss of oxygen (giving away oxygen)
oxidising ? are substances that cause another ? to be oxidises ie provide ? to the other substance. when an ? agent oxidises something - it itself loses ? ie is reduced
agents, substance, oxygen, oxidising, oxygen
reducing ? are substances that cause another ? to be reduced ie provide ? to the other substance/ remove ? from the other substance. when a ? agent reduces something - it itself gains ? ie is oxidised
agents, substance, electrons, oxygen, reducing, oxygen
in the reaction - CuO + Mg -» MgO + Cu - what is oxidised, reduced, the oxidising agent and the reducing agent
oxidised - Mg - magnesium
reduced - CuO - copper oxide
oxidising agent - copper oxide
reducing agent - magnesium
what is an ore and an example of an ore?
a rock that contains enough of the decided metal to be economical to extract the metal eg : hoematite - iron ore Fe2O3
which metals are extracted by electrolysis and why?
potassium, sodium, lithium, calcium, magnesium and aluminium - as they are the most reactive (as they’re above carbon) so are more difficult to extract
which metals are extracted by reduction?
zinc, iron, tin and lead
which metals are found native and are easily extracted and what are examples of these extractions?
copper, silver, gold and platinum - panning for gold
what is electrolysis? when we extract the metals by ? the compound containing it - and then passing ? through the liquid. then the metallic ? appears at the negative electrode called the ?
melting, electricity, element, cathode
which metals were among the first to be discovered and why?
silver and gold as they’re the easiest to extract
how are semi reactive metals like zinc extracted and in what?
they are extracted from their ores by reducing the oxide using carbon or carbon monoxide - in a blast furnace!
why is reduction preferable to electrolysis?
as it is relatively cheap, due to electrolysis being more expensive due to the large amount and high cost of electricity
what is another word for reduction using carbon?
smelting
due to higher grade ? being used up - it has become economic to extract some ? from certain ores which weren’t originally economic to ? from - so now they’ve turned to lower ? ores
ores, metals, extract, grade
when copper oxide and carbon powders are mixed together and heated what do you expect to see? (and why)
black with glittery red as the carbon has displaced the copper so it’s now carbon dioxide and copper - which is the glittery red
what is the positive electrode called and what are attracted to it?
anode, the negative ions - the anions
what is the negative electrode called and what are attracted to it?
cathode, cations - the positive ions
what happens when the cations are attracted to the cathode?
the metal ions gain electrons to make the metal
what happens when the anions are attracted to the anode?
they lose electrons and make the non metal element
is the metal ion positive or negative and what’s it called?
positive and it’s called the cation
is the non metal ion positive or negative and what’s it called?
negative, an anion
phyto mining is when - a plant is chosen that will ? the desired metal from the ? without dying - (these plants are called ?). they are grown and the ? metal collects in the leaves. the plants are ? after harvesting. the ash from the plants contains metal ? which the ? can be extracted from
absorb, soil, hyperaccumulators, desired, burnt, compounds, metal
3 pros of phytomining in comparison to traditional methods?
- there’s less waste
- smaller carbon footprint (more environmentally friendly)
- can extract metals from lower grade ores - increase supply of finite resource
3 cons of phytomining in comparison to traditional methods
- is a slower method
- plants grow in specific habitats - can’t grow everywhere
- uses a lot of land
bioleaching - uses ? to produce leachate solution that contain ? compounds, for example bacteria can convert ? copper sulphide into soluble copper ? which can then be dissolved into ? and extracted from the solution
bacteria, metal, insoluble, sulphate, water
3 pros of bioleaching compared to general/ traditional methods
- Less waste
- Low carbon footprint
- Takes less energy/ is more simple
disadvantages of bioleaching compared to traditional methods
- slow (especially in a cold climate)
- smelting would be cheaper
- hard to acquire bacteria, has to be safe therefore no anaerobic bacteria
Why are copper, gold, iron and aluminium mixed with smaller amounts of similar metals to make alloys?
because they’re too soft for most uses, so they are made harder for everyday use
what’s steel made from?
iron and a small amount of carbon
if you add chromium and nickel to steel what does it make - and why is this type of steel important?
stainless steel - as it’s in reactive
what is brass an alloy of??
copper and zinc - as the larger zinc atoms get in the way of the copper layers sliding making it harder
what is magnalium an alloy of and what does it do (because of what special features?) x
magnesium and aluminium - makes planes and expensive bikes - as it is strong, corrosion resistant and doesn’t corrode
what’s stainless steel used for
cutlery
why is brass used in musical instruments?
looks good and doesn’t corrode (can also be used for making door handles!)
4 main types of steel
mild, hard, stainless and tungsten steel
Mild steel properties and uses
easily worked and strong (has lost most brittleness) so good for car bodies and machinery
Hard steel properties and uses
Tough and brittle so used for tools eg a hammerhead
Tungsten steel properties and uses
Tough and hard at high temperatures - so drill bits and power saws
Stainless steel properties and uses
Tough, doesn’t corrode - used for chemical plant and cutlery
what is rust
3 details
the corrosion of iron
hydrated iron(III) oxide
reddy brown solid
what must iron be in contact with in order to rust?
both water and oxygen
what makes iron rust faster?
the presence of an ionic compound (eg: salt) dissolved in the water
how do most methods of rust prevention work?
by creating a barrier between iron and water and oxygen to prevent contact and therefore rusting
how does painting the iron surface, applying oil and grease etc stop rusting?
it’s a barrier method so stops water and oxygen coming into contact with iron
what is a sacrificial protection and how does it work (stopping rusting)
using a more reactive metal for protection - so it corrodes instead of the iron
what is galvanizing and how does it work?
covering steel with zinc - a barrier method - so the more reactive zinc will corrode instead
how does stainless steel prevent rusting?
it doesn’t corrode so the alloy of iron doesn’t rust
how does stainless steel prevent rusting?
it doesn’t corrode so the alloy of iron doesn’t rust
if an ? object is completely covered with a ? of another metal then the ? will not rust. this can be done by metal ? the object. often the coating can improve the ? of the iron, eg : chromium plating gives the object a very ? appearance
iron, coating, iron, plating, appearance, shiny
if an ? object is completely covered with a ? of another metal then the ? will not rust. this can be done by metal ? the object. often the coating can improve the ? of the iron, eg : chromium plating gives the object a very ? appearance
iron, coating, iron, plating, appearance, shiny
in electroplating the object that is going to be ? is made the cathode (so is given the ? charge) and dipped into a solution containing ? of the desired plating metal
plated, negative, ions
In the copper plating the key experiment what object is the anode?
impure copper
In the copper plating the key experiment which object is the cathode
The key
what is the solution used in the copper poring experiment and what ions is it split into?
copper sulphate so cu(2+) and so4(2-)
How does the key get electroplated in the copper plating the key experiment?
the Cu2+ ions from the copper sulphate are attracted to the cathode (the negative electrode) where the key is and the cu2+ ions gain electrons - making copper and plating the key
why is a life cycle assessment carried out?
to assess the environmental impact of a product in each stage of its life
what 3 things does a life cycle assessment consider?
- the useful life of a product
- materials and energy it takes to make the product
- what happens to the object on its disposal
5 main factors for a life cycle assessment :
- main requirements for ? input
- environmental ? and sustainability of making material from natural ?
- ? impacts of making the product from the ?
- environmental impact of using the ?
- environmental ? of disposing product by ? , landfill or recycling
energy,
impact, resources
environmental, material
product,
impact, incineration
main four steps of life cycle assessments?
raw materials, manufacturing, use and disposal
what 3 benefits does recycling metals provide us with?
- saves landfill space
- reduces need for further metal extraction
- reduces risk of running out of finite resources
in the copper plating the key experiment what happens to the anode(impure copper)
the impure copper is supplied with a positive charge and so becomes oxidised and becomes cu2+ which then replaces the copper in the solution (so replenishes the copper to keep being able to plate the key)
