Organic science Flashcards
Where are transition metals?
Between groups 2 and 3
What are properties of transition metals?
They form coloured compounds
Are generally (like all metals) hard, strong, shiny, malleable and conductive of heat/ electricity
They have high melting points (except mercury)
High DENSITIES
Properties of gold that make it useful for its purpose
Shiny, malleable, conductive of electricity and rust resistant so is used in electrical components.
Properties of copper that make it useful for its purpose
Malleable and corrosión resistant so is used in water pipes, is also a good conductor of electricity so can be used for electrical wiring.
Properties of iron that make it useful for its purpose
Is hard, tough, high density and so can be used for tools and building materials, is also malleable so can be used for car bodies
Is a catalyst in ammonia manufacturing
Titanium properties that make it suitable for its purpose
Is low density and high strength so can be used in fighter aircrafts, v resistant to corrosion so can be used in nuclear power pipes
Nickel properties suitable for use
Noncorrosive so can be used as coins
Which transition metals are used as catalysts?
Iron is used in the haber process in the production of ammonia.
Vanadium pentoxide is used for making sulphuric acid in the contact process.
Alloy
A mixture of 2 or more elements, one of which is a metal.
Why are regular metals not suitable for everyday uses?
The regular structure makes them soft as the layers can roll over one another.
Why are alloys stronger than normal metals?
Because the atoms of different sizes distorts the regular arrangement and so makes it harder for the atoms to slide over one another
What’s amalgam made up of and its use
Mercury (main metal) & is used in dental fillings
What’s brass made up of? Use?
Copper and zinc
Used for hinges and electrical plugs. (Where more friction is needed as is more malleable)
Solder use?
Lead and tin is used to join metals together
What are iron alloys called and made up of?
Steels, they are made by adding carbon (some other metals)
As steel is harder than iron, is less corrosive and so is used for bridges, engines, cutlery…
Bronze alloy and use
Copper and tin is used for medals and statues as is harder than copper
Gold alloy and use
Metals like zinc, copper, silver are used to strengthen gold. Can be used for jewellery
Aluminium alloys and use
Alloyed w small amounts of other metals to increase strength. Has low density and so can be used in aircrafts
Magnalium alloy and use
Aluminium and magnesium are mixed to make it stronger, lighter and less corrosive than aluminium. Is used for cars and aeroplanes .
High magnesium content is used for fireworks as is reactive and burns bright.
What type of reaction is corrosion of metals?
REDOX as the metal loses electrons (oxidised) while oxygen gains electrons (reduced)
What do metals corrode in the presence of?
Oxygen and water
Rusting
The corrosion of iron, (only in presence of oxygen and water)
Experiment to show that both oxygen and water are needed for iron to rust
1 put an iron nail in a boiling tube with just water (won’t rust). Boiling water beforehand will remove oxygen and oil can be used to stop air getting in.
2 put an iron nail in a tube w just air (won’t rust). Calcium chloride can absorb any water in the air.
3 put and iron nail in a boiling tube w air and water (will rust).
Ways to prevent rusting
Coating iron w a barrier, keeping water and oxygen out. Eg painting can cause a barrier.
On moving parts, oiling /greasing helps.
SACRIFICIAL protection involves placing a more reactive metal w the iron
Eg galvanising
What’s galvanising
Where a coat of zinc is put into an iron object to prevent rusting as zinc is more reactive and so will be oxidised easier and will corrode instead and acts as a barrier
Electroplating
Coating the surface of a metal with another metal using electrolysis
Process of electroplating
Cathode = object to electroplate
Anode = bar of metal to plate the object
Electrolyte = solution containing metal ions of the metal you are playing it with
The metal ions from the electrolyte move toward the cathode and is deposited on the object, the anode refills the metal ions in the solution
Homologous series
A group of chemicals that have the same functional group
Functional group
A group of atoms that determine how a molecule reacts.
Akkanes
A homologous series of saturated hydrocarbons
General formula of alkanes
CnH2n+2
First 4 alkanes
Methane, ethane, propane, butane
Number of bonds carbon atoms can make
4
Number of bonds hydrogen’s can make
1
Alkenes
A homologous series of unsaturated hydrocarbons containing a carbon-carbon double bond functional group
General formula of alkenes
CnH2n
First 3 alkenes
Ethene, propene, butene (but-1-ene, but-2-ene)
Test for alkenes
Shake the substance with bromine water and if it decolorises, it’s an alkene.
Why does bromine water turn clear in the presence of alkenes?
Because an addition reaction is taking place where bromine is added to the alkene double bond.
(Bromine is connected to the carbons)
Alkanes are saturated so this wouldn’t happen
Polymer
A substance of high average relative mo,educar mass made by joining repeating units of monomers.
Homologous series involved in addition polymerisation
Alkenes
What occurs during addition polymerisation? What is needed to make this occur?
The alkene monomer opens up its bond to form polymer chains w single covalent bonds. It needs pressure and a catalyst.
How do you draw the displayed formula of addition polymerisation?
Put an n before the alkene displayed formula of a monomer, draw an arrow (pressure and catalyst) and draw the alkane version of that alkene with bonds of both the ending carbons across brackets with an n after
Poly(ethene) properties and uses
Flexible, electrical insulator, cheap
Used for plastic bags, bottles and wire insulators
Poly(propene) properties and uses
Flexible, strong , tough, mouldable
Used for crates, furniture & rope
Poly(chloroethene) / PVC properties and uses
Tough and cheap
Used for window frames and water pipes
Poly(tetrafluoroethene) properties and uses
Un reactive, tough and non-stick
Used for nonstick pans and waterproof clothing
Condensation polymerisation
A process whereby many small monomer molecules join to form one large polymer with water or any other small molecule.
Difference between addition and condensation polymerisation
Addition polymerisation has all of the atoms in the monomer ending up in the polymer whereas condensation polymers are formed along with other small molecules formed with each new bond formed.
Also addition monomers are all alkenes whereas condensation polymers have monomers with more than one functional group to create alternating monomers within the polymer.
How are condensation polymers formed?
2 different monomers each with 2 of the same functional groups react together, producing small molecules as a byproduct.
Polyester
A condensation polymer formed via the reaction of a dicarboxylic acid and a diol to form an Ester link. With each ester link, amole uke of water is formed.
General formula of an alcohol
CnH2n+1OH
Functional group of alcohols
‘-OH’
First 4 alcohols
Ethanol, propanol, butanol, pentanol
What happens when alcohols are oxidised?
They form carboxylic acids
General formula of carboxylic acids
Cn-1H2n-1COOH
Functional group of carboxylic acids
‘-COOH’
First 4 carboxylic acids
Methanoic acid, ethanoic acid, propanoic acid, butanoic acid
What catalyst is used in the production of polyesters?
Sulfuric acid catalyst
Naturally occurring polymers
DNA - contains 2 strands of nucleotide monomers that bond in a polymerisation reaction.
Amino acid- form polymers via condensation polymerisation which are proteins which are v important for enzymes.
Carbohydrates- molecules of carbon, hydrogen and oxygen which are sugar monomers that form a large polymer known as starch or cellulose
What’s plastic made from?
Crude oil
What are the 3 ways to dispose of polymers?
Landfill sites
Incineration (combustion)
Recycling
Pros of landfill sites
Polymers can be expensive and difficult to recycle
Cons of landfill
Uses up valuable land
Most polymers are non biodegradable so will stay in landfill for long time.
Pros of incineration
Produces much energy that can be used in generation of electricity
Cons of incineration
Can release toxic gases
Carbon dioxide contributes to global warming
Pros of recycling
Reduces no biodegradable waste in landfill
Reduces greenhouse gases and toxic emissions released in incineration
Uses less water and energy resources than producing new polymers
Preserves crude oil
Saves money and creates jobs
Cons of recycling
Polymers have to be separated before melted/ reformed which can be difficult and expensive
Mixed polymers can reduce quality of products
Recycling is finite as polymer strength decreases over time
Melting of polymers can release emissions that are harmful to plants and animals .
Fuel cells
Cells that will produce a voltage continuously as long as they are supplied with a fuel and oxygen and produce electricity via the reaction of a fuel with oxygen.
Where are hydrogen-oxygen fuel cells used?
In cars/spacecraft
What type of reaction ocurrs in a hydrogen oxygen fuel cell?
Exothermic, meaning energy levels in the reactants are higher than energy levels in the products
What energy transfer occurs in hydrogen oxygen fuel cells?
Chemical to electrical
Exothermic
- transfer energy to the surroundings
Endothermic
Take in heat from the surroundings
Advantages of hydrogen oxygen fuel cells
No moving parts (no energy lost via friction) Compact Lightweight Zero emissions (only water byproduct) Renewable energy Provides voltage as long as supplied Quiet Requires less maintenance Replaces batteries that are polluting
Disadvantages of hydrogen oxygen fuel cells
Manufacture of hydrogen involves use of fossil fuels, producing greenhouse gases
V flammable and so dangerous
Expensive
Needs to be stored in pressurised reenforced containers, taking up more space than liquid fuels like petrol.
Overall reaction in hydrogen oxygen fuel cells
Hydrogen + oxygen > water
Fuel cell
A type of chemical cell that’s supplied with a fuel and oxygen and uses energy from the reaction between them to produce electrical energy efficiently.
Chemical cells
Produce a voltage until until one of the reactants is used up.
The reactivity series
Potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead, hydrogen, copper, silver, gold
Nanoparticles
Particles below 100 nanometers
(roughly 100 atoms across)
Fullerenes
Nanoparticles, including nanotubes made up of carbon and joined via strong covalent bonds.
Important property of nanoparticles
Have a high surface area to volume ratio which means they hold different properties to larger particles as a greater proportion of atoms can interact with substances they come into contact with.
Uses of nanoparticles (nanoscience uses)
CATALYSTS due to high surface area to volume ratio (more surface= more collisions= higher rate of reaction)
COSMETICS (eg sunscreen) allow protection yet transparency
NANOMEDICINE absorbed more easily by the body and so can deliver drugs straight to cells
LUBRICANT COATINGS (Eg artificial joints and gears)
ELECTRIC CONDUCTORS can be used for circuits in computer chips
PLASTICS in sport equipment as make strong while keeping mass low
SURGICAL MASKS have polymer fibres where silver nanoparticles are added to create antibacterial properties
Disadvantage of nanoparticles
No full understanding of how they affect the body (need to be tested)
Don’t know long term health / side effects are
Eg some nanoparticles don’t break down easy and so can build up in cells and can cause lung inflammation if breathed in
Types of polymer
Strong & rigid polymers (polyethene) for water pipes
Light & stretchy (low density polyethene for plastic bags and bottles
Polystyrene foam for packaging/thermal insulators
Heat resistant (melamine resin/polypropene) for plastic kettles
Ceramics
Include glass, porcelain and bone China.
Are made by baking substances to produce a brittle, stiff material.
Clay
Mineral formed from weathered and decomposed rock.
Soft when dug up so is easy to mould into different shapes for pottery/ bricks.
Can be hardened by firing at very high temperatures
Ideal as building material.
Glass properties
Transparent & strong
Can be mounded when hot and brittle when thin
Majority of glass made from soda-lime glass, made by heating limestone, sand and sodium carbonate until melting point, cool as glass.
Composites
(Eg fibreglass/ concrete)
Made of one material (reinforcement) embedded in another (matrix/binder).
Properties depend on materials it’s made from.
Production of carbon fibre
Bonded carbon atoms to make carbon fibres or nanotubes held together by polymer resin matrix.
Expensive to manufacture.
Properties of carbon fibre
Light and strong so are good for aerospace and sports car manufacturing
Metal properties
Good conductor of heat/electricity, high density, malleable
Can be mixed to form alloys.
Polymer properties
Flexible, adaptable, mouldable, cheap, less dense, thermal/electrical insulator.
Degrade over time so aren’t long lasting.
Ceramics properties
Heat/electricity insulator, brittle, stiff, strong, hardwearing, don’t degrade so are long lasting
Metals properties
Conductors of heat/electricity, malleable, (corrosion resistant) metals can last long, less brittle so don’t shatter.
Composites properties
Vary depending on reinforcer and matrix, designed for specific properties for specific purpose,
Disadvantage is expensive
Word equation for the complete combustion of ethene
Ethene + oxygen > carbon dioxide + water
How many nucleotides make up the polymer DNA?
4 (two strands )
