C1- Carbon Chemistry Flashcards
What does **finite resources **mean?
Are no longer being made or are being made extremely slowly such as fossil fuels
What is a non-renewable resource?
Are being used up faster than they are being formed, such as fossil fuels
What are the difficulties associated with the finite resource of crude oil?
- all readily extractable resources will be used up in the future
- finding replacements
What is crude oil made up of?
A mixture of many types of oil, which are all hydrocarbons
What is a hydrocarbon?
Made up of molecules containing **carbon **and hydrogen ONLY
Where does crude oil get separated?
In a fractional distillation column
How does the **temperature gradient **work in the fractional distillation column?
- Oil that doesn’t boil sinks as bitumen, a thick liquid at the bottom with a very high boiling point.
- Other fractions boil and their gases rise up the column
- The column is cooler at the top, so fractions with lower boiling points exit at the top
What are the forces between molecules?
- Forces between molecules are **intermolecular forces **and are broken during boiling
- Liquid separates as gas molecules
How do larger molecules get separated?
They have strong forces of attraction, so a lot of energy is needed to break the forces between molecules, so they have high boiling points
How do smaller molecules get separated?
They have weaker attractive forces and are easily separated. Less energy is needed to break the forces between the molecules and have low boiling points
How does **transporting **crude oil cause problems?
- Oil slicks can damage birds’ feathers and cause death
- Clean-up operations use detergents that can damage wildlife
What are the **political **problems with extracting crude oil?
- UK is dependent on oil and gas from politically unstable countries
- Oil-producing nations set up high prices and cause problems for the future supply of non-oil producing nations
What does the process **cracking **do?
Turn large alkane molecules into smaller alkane molecules and **alkene **molecules
Why is the alkene molecule useful?
It has a double bond, which makes it useful for making polymers
Why does cracking help oil manufacturers?
It helps match supply with demand for products like petrol
What are the factors influencing the choice of fuel?
- energy value
- availability
- storage
- cost
- toxicity
- pollution caused
- ease of use
Why is the amount of fossil fuels being burnt increasing?
Populations are increasing
What are the concerns of the increase in fossil fuels?
More carbon dioxide emissions could result in the speeding up of Global Warming
What is the equation for **complete **combustion?
hydrocarbon + oxygen → carbon dioxide + water
What is the equation for **incomplete **combustion?
fuel + oxygen → carbon monoxide + carbon + water
What are the differences between complete and incomplete combustion?
- more **energy **is released during complete combustion
- **toxic **gas (carbon monoxide) and soot (carbon) is made during incomplete combustion
What is clean air made up of?
- 78% nitrogen
- 21% oxygen
- 1% - only 0.035% carbon dioxide
Why do the percentages only change by a small amount?
There is a balance between the processes that use up and make both CO2 and O2. As the carbon cycle shows
How has the percentage of carbon dioxide in the air increased?
- deforestation (less photosynthesis can take place)
- increased population (world’s energy requirements increase, so more factories producing pollution)
What formed the atmosphere?
Gases escaping the interior of the Earth
How did the Earth get oxygen?
The plants that could photosynthesise removed carbon dioxide from the atmosphere and added oxygen
What supposedly caused oceans?
The water vapour condensed to form oceans and the carbon dioxide dissolved in the water
What does sulfur dioxide cause?
When dissolved in water, it forms acid rain that damages wildlife and limestones buildings/ statues
What does a catalytic converter do?
Changes carbon monoxide to carbon dioxide
What reaction takes place in a catalytic converter?
Nitric oxide and carbon monoxide react on the surface of the catalyst and form natural components of air - nitrogen and carbon dioxide.
2CO + 2NO → N2 + 2CO2
What is the definition of a hydrocarbon?
A compound of carbon and hydrogen atoms ONLY
What are alkAnes?
Hydrocarbons that have single covalent bonds only
What are alkEnes?
Hydrocarbons that have a double covalent bond between carbon atoms
What experiment is used to test for an alkene?
When orange bromine water is added to an alkene it turns colourless (decolourises). The colourless compound formed is a di-bromo compound by an addition reaction
What is a saturated compound?
One that has single covalent bonds between carbon atoms, such as alkanes
What is an unsaturated compound?
One that has at least one double covalent bond between carbon atoms, such as alkenes
What is addition polymerisation?
The process in which many alkene monomers react to give a polymer.
What does the polymerisation reaction need to be able to happen?
- high pressure
- catalyst
What is the displayed formula of ethene?
What is the displayed formula of poly(ethene)
What is the addition polymerisation reaction?
Many unsaturated monomer molecules (alkenes) form a saturated polymer
What are the properties of nylon?
- tough
- lightweight
- keeps water out
- keeps UV light out
- water vapour cannot enter/leave
What are the properties of GORE-TEX?
- same properties as nylon
- breathable (water vapour can pass through the membrane but rainwater cannot)
How is GORE-TEX breathable?
- it is made from a PTFE (polytetrafluoroethene) / polyurethane membrane
- holes in PTFE are too small for water to pass through but are big enough for water vapour to pass through
What is done to PTFE to make it stronger?
It is laminated onto nylon
What polymers are scientists trying to develop?
- polymers that dissolve
- biodegradable polymers
What are the environmental and economic issues with use of existing polymers?
- disposal of non-biodegradable polymers means landfill sites get filled quickly
- landfills waste land that could be valuable
- disposal by burning makes toxic gases
- disposal or landfills wastes the crude oil that was used to make polymers
- difficult to sort out different polymers, so recycling is hard
What are atom in polymers held by?
strong covalent bonds
What are the properties of plastics?
- weak intermolecular forces between polymer molecules
- low melting points
- stretched easily (polymer molecules slide over each other)
What are the properties of plastics with strong forces?
- high melting point
- cannot be stretched
- rigid
How are protein molecules changed when cooked?
- permanently change shape (denaturing)
- texture changes
What happens when a carbohydrate is cooked?
- starch grains swell up and spread out
- cell walls rupture
- resulting in loss of rigid structure
- soft texture produced
What happens when sodium hydrogencarbonate is heated?
It decomposes to give carbon dioxide
sodium hydrogencarbonate → sodium carbonate + carbon dioxide + water
2NaHCO3 → Na2CO3 + CO3 + H2O
What are emulsifiers?
Molecules that have a water-loving (hydrophilic) part and an oil/fat-loving (hydrophobic) part
How does and emulsifier stop water and oil from separating?
- hydrophilic end bonds to water molecules
- hydrophobic end bonds to oil/fat molecules
- hydrophilic end attracted to water molecules, which surround the oil, keeping them together
What is the equation for making an ester?
alcohol + organic acid → ester + water
What experiment can be done to make an ester?
- acid is added to alcohol and heated for some time
- condenser stops the gas from escaping and helps cool it down again, so it can react more
- condenser allows the reaction to go on longer
What properties must a perfume have?
- evaporate easily (to reach the nose)
- non-toxic
- not react with water (so does not react with perspiration)
- not irritate the skin (so can be put directly onto skin)
- insoluble in water (so cannot be washed off easily)
What is a solution?
A mixture of solvent and solute that does not separate out
Explain volatility (ease of evaporation) of esters, in terms of kinetic energy
- in order to evaporate, particles in a liquid need sufficient kinetic energy to overcome forces of attraction to other molecules in liquid
- weak attractions exist between particles of the liquid, so is easy to overcome these attractions
Why does water not dissolve nail varnish?
- attraction between water molecules is stronger than the attraction between water molecules and nail varnish molecules
- attraction between nail varnish molecules is stronger than the attraction between water molecules and nail varnish molecules
What is a colloid?
Particles are mixed and dispersed with particles of a liquid but not dissolved
Why will the components of a colloid not separate?
Particles are scattered or dispersed throughout the mixture and are too small to settle at the bottom
Why do most paints dry?
- paints are applied as a thin layer
- solvent evaporates
How do water (emulsion) paints dry?
Solvent evaporates and oil forms a protective skin
How do oil paints dry?
- solvent evaporates
- oil is oxidised by atmospheric oxygen
What are thermochromic pigments?
Change colour at different temperatures
What are thermochromic pigments used for?
- cups/mugs
- fridges
- electric kettles
- babies’ spoons and bath toys
What are phosphorescent pigments?
Glow in the dark
How do phosphorescent pigments glow in the dark?
- absorb and store energy
- release energy as light over a period of time
Why are phosphorescent pigments better than radioactive paints?
They are safer
