Chemistry 1a-b Flashcards
Why is it important to recycle metal?
Because it only uses a small fraction of the energy needed to mine and extract new metal e.g. recycling copper only takes 15% of the energy needed to mine and extract new copper. Recycling also cuts down the amount of waste in landfill sites
What is the structure of alkanes?
They are made up of chains of carbon atoms, surrounded by hydrogen atoms, different alkanes have different chains of different lengths
What happens if a metal corrodes?
It looses its strength and hardness
What are unsaturated vegetable oils at room temperature?
Liquid
What are the pros of ethanol?
When the fuel is burnt, the CO2 released is absorbed by the plant as it grew-carbon neutral. The only other product is water
Why are hydrogenated oils more useful as spreads for baking cakes and pastries?
Because they have a higher melting point than unsaturated oils so they are more solid at room temperature
What does increasing carbon dioxide cause?
Climate change
What is phytomining?
Growing plants in soil that contains copper. The plant cant use or get rid of the copper so it builds up in the leaves, copper can then be collected in the ash once the plant is burnt in a furnaces
Alternatives to crude oil are available so why do we use so much of it?
Cars are designed for petrol/diesel, its readily available and it is more reliable too e.g. solar and wind power need the right conditions to work
What is the worst case scenario for when oil will run out?
About 25 years
What size can compounds be?
Small molecules like water to big lattices like sodium chloride
Why are properties of compounds different to the original elements?
Because it is a mixture of properties
What are the two ways to chemically extract metal from ores?
Reduction or electrolysis (splitting it with electricity). Some metals have to be concentrated before extraction (to get rid of the unwanted rocky material)
What are group 1 elements?
Metals that react in the same way eg react with water to form an alkaline solution + hydrogen and react with oxygen to form an oxide
What are the disadvantages of this method?
The ethanol isn’t very concentrated so if you want to make it stronger, you have to distill it and purify it
What is the symbol for calcium carbonate?
CaCO3
Atoms join together via chemical bonds to make what?
Compounds
What is an example of covalent bonding?
HCl, a hydrogen atom shares an electron with chlorine
What other substances thermally decompose in the same way?
Magnesium, copper, zinc and sodium carbonate
Why is this not a reliable way to produce ethanol?
Because ethene is made from crude oil which is non renewable and could run out soon, making ethanol from ethene will become very expensive
Positives and negatives of limestone products?
Widely available, cheap, more hard-wearing than marble, looks ok, concrete is very quick and cheap but ugly. Limestone products don’t rot or get eaten by rodents and insects, fire resistant and concrete doesn’t crack, corrode and can be reinforced with steel bars for more strength
What is the formula for Propane?
C3H8
What are the first four alkanes?
Methane, Ethane, Propane and Butane
Where is crude oil used?
Cars, boats, trains, planes, central heating systems and power stations
What are the cons of biodiesel?
We cant make enough to completely replace normal diesel. Its expensive to make and farmers could switch to grow crops for biodiesel, increasing food prices
What do electrons occupy?
Electron shells sometimes called energy levels
Why do we want to crack long chain hydrocarbons?
Because long chain hydrocarbons form thick gloopy liquids like tar which isn’t that useful so a lot of longer chained hydrocarbons, are turned into smaller ones via cracking
What does electrolysis mean?
Splitting up with electricity
How does the profitability of metal extraction change over time?
If the price for the metal drops, extraction isn’t worth it, if it increases then it is worth extracting it. Technology can make it possible to extract more making it easier and possible to extract metal that wasn’t worth it before
What is crude oil formed from?
Buried remains of plants and animals-its a fossil fuel
what are the properties of titanium?
Low density but is very strong and corrosion resistant. Good for replacement hips
Why can’t you do some of these reactions in a school?
Because a bunsen burner can’t reach a high enough temperature to thermally decompose some carbonates of group 1 metals
What other carbonates react with acids?
Magnesium, copper, zinc and sodium
How can poly(ethene) have different properties?
At 200°C and 2000 atmosphere pressure it is flexible and has a low density whereas at 60°C and a few atmosphere pressure with a catalyst it is rigid and dense
What happens when calcium carbonate is heated?
It thermally decomposes to make calcium oxide and carbon dioxide
As well as fuels, what else does crude oil provide?
Raw materials for making various chemicals including plastics
Why is electrolysis more expensive than reduction with carbon?
Because it uses a lot more energy
What does a compound formed from a metal and non metal consist of?
Ions
What does it mean if an alkane has shorter molecules?
The shorter the molecules means it is more runny, less viscous, more volatile (Turn into gas at a lower temperature) lower boiling point and more flammable hydrocarbon
What are similar basic properties of metals?
They are strong but can be bent or hammered into different shapes, they are good at conducting heat and conducting electricity
How does sulfur dioxide cause acid rain?
When it mixes with the clouds it makes dilute sulphuric acid which then falls as acid rain
Why are vegetable oils good in food?
They provide a lot of nergy, they contain lots of nutrients e.g. oils from seeds contain vitamin E and also vegetable oils contain essential fatty acids for metabolic processes
Biodiesel is another new fuel, What is it?
It is another biofuel and can be produced from vegetable oils such as rapeseed oil and soybean oil. Biodiesel can be mixed with ordinary diesel fuel to run a diesel engine
What are two examples of new methods to extract copper?
Bioleaching and phytomining
Why are alloys harder than pure metals?
Because different elements have different sized atoms so when an alloy is made, the layers become irregular and can no longer slide past each other
What are particles of soot and ash doing in the world?
Causing global dimming
What is the formula for Ethane?
C2H6
What metals have to be extracted with electrolysis?
The metals that are higher than carbon in the reactivity series, but electrolysis can be expensive
what is an example of reduction?
Iron oxide becomes iron
You have the same atoms at the start and end of chemical reactions, but what happens to them?
They get arranged in different ways
What are acid gas scrubbers?
They take the harmful gasses out before they are released into the atmosphere
What are the elements in the final group (group 0)
Noble gasses
What sort of fuels are being developed?
Altenative fuels, many are renewable fuels so they won’t run out however there are still pros and cons
What are the first tow alkenes?
Ethene and Propene
Do metal atoms gain or lose electrons?
They lose electrons to form positive atoms
Why are saturated fats less healthy?
They increase the amount of cholesterol in your blood which can block arteries and increase the risk of heart disease
How many electrons can fill the first shell?
2 electrons
What are the cons of ethanol?
Engines have to be converted before ethanol can be used as a fuel and ethanol fuels aren’t widely available. As demand increases, farmers may switch from growing food crops to growing crops to make ethanol which would increase food prices
What does electrolysis require?
A liquid to conduct electricity called the electrolyte
What sort of bonds do unsaturated oils contain?
Double bonds between some of the carbon atoms in their carbon chains, this is why they decolourise bromine waters the double bond opens up, saturated fats have no double bonds
What do elements in the same column have in common?
They have similar properties
How is oil extracted from plant material?
It is crushed and the pressed between two metal plates to squash the oil out, this is the traditional method of producing olive oil
What is cupronickel made out of?
Copper and nickel - hard and corrosive resistant, used to make ‘silver’ coins
What are the benefits of using vegetable oils for cooking?
Higher boiling point than water means foods can be cooked at higher temperatures quicker, it adds a different flavour as oil carries the flavour and stops food sticking to the pan
How is the alcohol in beer and wine made?
By fermentation
What are newly discovered uses for polymers?
Waterproof coatings for fabrics, dental polymers for tooth fillings, polymer hydrogel wound dressings, new biodegradable packaging materials from polymers and cornstarch are being produced
How many bonds do the carbon and hydrogen atoms make?
Hydrogen still only forms one but carbon forms four as it has a double bond
What is an example of polymerisation?
Many single ethenes + pressure and a catalyst = poly(ethene)
Do elements in the same group have the same or different number of electrons in their outer shell?
The same amount of electrons in their outer shell
The atoms form bonds with as many other atoms as they can, what does this tell us about them?
They are saturated
Can you separate two original elements out again from a compound?
It’s usually difficult
What are the properties of aluminium?
It is corrosion resistant and has a low density, pure aluminium isn’t that strong but it forms hard, strong alloys. Good for making aeroplanes
In chemical reactions, what does the mass of reactants equal
The mass of products, e.g. 6g magnesium reacted with 3g oxygen = 10g magnesium oxide
How can acid rain be reduced?
By reducing sulfur emissions
What are electrolytes usually?
Metal salt solutions made from the ore or molten metal oxide. It has free ions which conduct the electricity making the whole thing work
What is metal fatigue?
When a metal becomes too stressed and strained repeatedly over time, leading to the metal breaking. This can be dangerous especially in aeroplanes
WhAT ARE MOST OF THE PRODUCTS OF CRACKING?
Alkanes and unsaturated hydrocarbons call alkenes
How many electrons do noble gasses in their outer shells?
8, except for helium which has two, they are stable and un-reactive
Why do crude oil fraction make good fuel?
Because they burn clearly
Why are the two bonded atoms strongly attracted to each other?
Because they have opposite charges
Hydrogen gas in another new fuel, what is it?
It can be used to power vehicles, the hydrogen comes from the electrolysis of water and there is plenty of water around but it takes up electrical energy which doesn’t come from renewable sources
What are the properties of copper?
Good conductor of electricity so good for electrical wires, hard and strong but can be bent and doesn’t react with water. Good for plumbing
What is this type of bonding called (giving/taking electrons)?
Ionic bonding
Are atoms lost or made in chemical reactions?
Neither, atoms aren’t lost or made in chemical reactions
Where are vegetable oils used?
In food
Where can we extract oil from?
Plants- some fruits and seeds contain a lot of oil
What is margarine made from?
Partially hydrogenated vegetable oils, all the double bonds becoming single bonds would be too hard to spread so hydrogenating most of them make it a better consistency
What do formulas show?
What atoms are in a compound
What are the pros of biodiesel?
It is carbon neutral, engines don’t have to be converted, it produces a lot less sulfur dioxide and particulates than other diesel or petrol
What are ores usually?
An oxide of the metal e.g. the main aluminium ore is bauxite-aluminium oxide
What does a compound formed from non metals consist of?
Molecules
Why are gold alloys used to make jewellery?
Because pure gold is too soft so zinc, copper, silver, palladium and nickel are added
Do atoms prefer to have full or incomplete outer shells?
Atoms are happier when they have full outer shells like the noble gasses
What do monounsaturated fats contain?
One c=c bond somewhere in their carbon chains, polyunsaturated fats have more than one c=c bond
What are the pros of hydrogen gas?
Hydrogen combines with oxygen in the air to form just water so it is very clean
What does the use of each hydrocarbon depend on?
The volatility and viscosity
What is the formula for Butane?
C4H10
What metals have to be extracted with reduction using carbon?
The metals below carbon in the reactivity series because carbon can only remove the oxygen from metals that are less reactive than itself
What energy level (shell) is filled first?
The lowest shells are filled first, those closest to the nucleus
Why is the amount of carbon dioxide increasing?
Because large amounts of fossil fuels are being burnt
What are hydrocarbons?
Fuels such as petrol and diesel made of carbon and hydrogen
What is a mixture?
Two or more elements or compounds that aren’t chemically bonded together
What is the bad point about crude oil?
Most scientists think oil will run out one day, it is non renewable
What is the general formula for alkanes?
CnH2n+2
What are the issues of quarrying limestone?
Ruins landscapes, noise pollution, lots of dust, destroys habitats, more noise and other pollution from lorries transporting limestone, sight pollution
How is electrolysis used to get copper?
Electrons are pulled off copper atoms at the anode causing them to go into solution as Cu2+ ions. Cu2+ ions near the cathode gain electrons and turn back into copper atoms. The impurities are dropped at the anode as a sludge whilst the pure copper atoms bond to the cathode
What is an example of something that has to be extracted with electrolysis?
Aluminium
What is an example of cracking?
Kerosene with ten carbon atoms (too much of this in crude oil) become octane, eight carbon atoms and useful for petrol + ethene, two carbon atoms and is good for making plastics
What is the layout of the periodic table?
First two columns=reactive metals Next ten columns=transition metals Ten elements (diagonal)=other metals Group 3-4-5-6-7= non metals Group 0=noble gasses Diagonal line separates metals and non metals
How many electrons can occupy the second, third etc shells?
8 electrons
What is polymerisation?
Joining lots of small alkene monomers to make long chain molecules called polymers
What can alkenes be used to make?
Polymers
What can you use to extract copper from a solution?
You can extract copper from a solution using a displacement reaction
What type of binding is this?
Covalent, this is when each atom shares electrons. Enough covalent bonds must be formed to fill up the outer shells
What is the issue with pure iron?
It is too bendy as it usually has 2% of impurities such as carbon making it stronger
How many bonds do the hydrogen and carbon atoms make?
Carbon makes four, hydrogen make one
How can sulfur emissions be reduced?
By taking the sulfur out of the fuel before it is burnt although this costs more and takes more energy which can mean releasing green house gasses such as carbon
What is an example of things that contain oil?
Brazil nuts, peanuts and sesame seeds contain a lot of oil which can be extracted and used for food or fuel
What is complete combustion and when does it happen?
When all the fuels burn it is complete combustion, this happens when there is plenty of oxygen available
What is thermal decomposition?
He one substance chemically changes into at least two new substances when its heated
How can each part of crude oil be separated?
Each fraction can be separated by fractional distillation
What is an example of a displacement reaction
Copper sulfate + iron = iron sulfate +copper
What happens once the oil has been extracted?
Distillation refines the oil and removes water, solvents and the impurities
Why do we balance equations?
Because there must be the same amount of each element on both sides
What are the alternatives to using oil?
Using renewable energy sources
In most atoms are the outer shells full?
No, this makes the atom want to react to fill its outer shell
What are ores?
They contain metal to make extraction worthwhile
Why are alloys good?
Because you can mix metals together to get the desired properties
How can you test for an alkene?
By adding the substance to bromine water, an alkene will decolourise the bromine water turning it from orange to colourless because the double bond open up and forms bonds with the bromine
Do non metal atoms gain or lose electrons?
They gain electrons to form negative ions
How are metals extracted by reduction?
Metal can be extracted by reduction with carbon, it is when oxygen is removed. The position of the metal in the reactivity series shows if it can be extracted by reduction with carbon
What else can limestone be used for?
Powdered limestone, heated in kiln with powdered clay makes cement. Cement mixed with sand and water makes mortar (sticks bricks together) or cement mixed with sand and aggregate makes concrete
What sort of reaction is cracking?
It is a thermal decomposition reaction, breaking down molecules by heating them
What is the raw material for fermentation?
Sugar which is converted into ethanol using yeast
What is an alternative way of cracking?
Mix the vapour with steam at a very high temperature
What are three types of steel (and their properties/uses)?
Low carbon steel (0.1% carbon) is easily shaped so good for car bodies. High carbon steel (1.5% carbon) is very hard and not flexible making it good for blades for cutting tools and bridges. Stainless steel (chromium and sometimes nickel are added) is corrosion resistant so it is good for cutlery and containers for corrosive substances
Why is pure iron bendy?
Because it has a regular arrangement of identical atoms making it easy for the layers to slide over each other
What do you get when you react calcium oxide with water?
Calcium Hydroxide
Alloys are ______ than pure metals?
Harder
Is calcium hydroxide acid or alkaline?
Alkali, used to neutralise acidic soil in fields, powdered limestone can do this too but calcium hydroxide is faster
What is the word equation for this?
Sugar=Carbon dioxide+ethanol
Although polymers are cheap, what are the disadvantages?
They aren’t biodegradable, they’re not broken down by microorganisms so they don’t rot and they are difficult to get rid of so they fill up landfill sites which is why you should re use them
Why are aluminium alloys used to make aircrafts?
Because aluminium has a low density but alloyed with small amounts of other metals it is stronger
Why are alkenes unsaturated?
Because they could make more bonds by opening up the double bond allowing the two carbon atoms to bond with other atoms
What does cracking mean?
Splitting up long chain hydrocarbons by passing vapour over a hot catalyst
Why are partially hydrogenated vegetable oils often used instead of butter?
These oils are cheaper and stay in date longer making processed foods like biscuits cheaper with a longer shelf life
What are elastic polymer fibres used for?
Very-stretchy LYCRA fibre for tights
What is bioleaching?
Using bacteria to separate copper from copper sulfate. The bacteria gets energy from the bond between copper and sulfur, separating the copper from the ore in the process. The leachate contains copper which can be extracted by filtering
What is global dimming?
In some places, 25% less sunlight is reaching earth caused by soot and ash produced when fossil fuels are burnt
What is the process of cracking?
Heat the long-chain hydrocarbon to vaporise it then the vapour is passed over a powdered catalyst (aluminium oxide) at a temperature of about 400°C-700°C
What is the formula for Methane?
CH4, there is one carbon atom, surround by four hydrogen atoms
What happens to the electrons in electrolysis?
They are taken away by the (positive) anode and given away by the (negative) cathode.
What can electrolysis also be used for?
To purify extracted metal
What are light, stretchable polymers used for?
Plastic bags e.g. Low density poly(ethene),
How do the particles of soot and ash cause global dimming?
These particles reflect sunlight back into space or can help to produce more clouds which reflect the sunlight back to space
How can crude oil be extracted?
By drilling and pumping
What is the general formula for alkenes?
CnH2n
How are most metals extracted from their ores?
By using a chemical reaction
What is limestone good for?
For making blocks for buildings like cathedrals as it is sturdy and doesn’t react with anything
What happens when you react ethene with steam in the presence of a catalyst?
You produce ethanol
What are vertical columns called?
Groups
Why are natural unsaturated fats such as olive oil and sunflower oil good for you?
They reduce the amount of blood cholesterol but eating lots of partially hydrogenated vegetable oil can still cause heart disease.
What is the formula for ethene?
C2H4
What can calcium hydroxide used to test?
To test for carbon dioxide. Cloudiness = carbon dioxide. Calcium hydroxide+carbon dioxide=Calcium carbonate+water
What is bronze made out of?
Copper and tin - harder than copper and good for making medals and statues
What is the formula equation for combustion of hydrocarbons
Hydrocarbon + oxygen = carbon dioxide + water vapour
Why will polymers soon become more expensive?
Because crude oil is running out and they are products of crude oil
Apart from shorter chain hydrocarbons, what else does cracking produce?
Ethene which is needed for making plastics
What is hydrogenation?
When unsaturated vegetable oils are hardened by reacting them with hydrogen with a nickel catalyst at about 60 °C, the hydrogen reacts with the double bonded carbons and opens out the bonds
What does the type of salt made depend on?
The acid used e.g.. sulphuric acid=calcium sulphate or hydrochloric acid=chloride
What is the disadvantages of partially hydrogenated oils?
You end up with lots of trans fats, and there is evidence that these are very bad for you
How do you work out the electronic structure?
By looking at the amount of protons-atomic number-bottom number, then remember that 2 electrons in first shell then a maximum of 8 in the others
Why is it important to recycle as much copper as possible?
Because the supply of copper rich ore is limited and the demand is growing which can lead to shortages in the future
Why is acid rain bad?
Because plants and animals die as a result of the lakes becoming acidic
What is a metal ore?
A rock that contains enough metal to make extraction worthwhile
What is limestone mainly?
Calcium carbonate
What does sulfur dioxide cause when it is released?
Acid rain
What happens if you put a reactive metal into a solution of a dissolved metal compound?
The reactive metal will replace the less reactive metal in the compound because the reactive metal bonds more strongly to the non metal bit of the compound and pushes out the less reactive metal
What is the order of condensation of crude oil (fastest to slowest/bottom to top)?
Bitumen, oil, diesel, kerosene (jet fuel), naphtha, petrol
Copper is extracted by reduction with copper then smelted, why does it still need electrolysis?
To purify it so it can conduct electricity better, but it is quite expensive
What are the positive points of limestone?
Makes useful things like houses and roads. Chemicals for dyes, paints and medicines. Can neutralise acidic soil and lakes after acidic rain. Neutralises sulfur dioxide from power station chimneys to stop acidic rain. Quarries make jobs, improve economy and after the landscape is restored
How do you balance equations?
By adding numbers to the FRONT of the formulae where needed
What are two other ways oil can be removed?
A centrifuge or solvents
Crude oil is mostly hydrocarbons, what are the hydrocarbons called?
Alkanes
Why do the different hydrocarbons keep their original properties and condensing points?
Because they aren’t chemically bonded
What happens when calcium carbonate reacts with acid?
It makes calcium salt, carbon dioxide and water
One of the new fuels is Ethanol, What is ethanol?
It is produced from plant material so it is known as a biofuel, it is made by fermentation of plants and is used to power cars in some places, it is often mixed with petrol to make better fuel
What is the symbol equation for this?
Ca(OH)2 + CO2 = CaCO3 + H2O
What is an example of ionic bonding?
NaCl, a sodium atom gives an electron to a chlorine atom
What are the issues of making things with limestone?
Cement factories produce dust, causes breathing problems for some people. Energy is needed which usually comes from burning fossil fuels (pollution)
What can oils such as rapeseed oil and soybean be processed and turned into?
Fuel (biodiesel), they are very suitable because they contain a lot of energy.
How can you protect a metal from corrosion?
By painting it
What are everyday uses of metals?
Strength and can be shaped makes them good for bridges and car bodies. Good for saucepan bases so heat can travel through and their conductivity makes them good for electrical wires
What sort of molecule chains do oils and fats contain?
Long chain molecules with lots of carbon atoms, they are either saturated or unsaturated
What is smelting?
Heating the ore in a furnace
How do you get limestone?
From quarries
What are the cons of hydrogen gas?
You need a special and expensive engine and hydrogen isn’t widely available, you still need energy from other sources to make it, also hydrogen is hard to store
What is global warming?
The extra carbon dioxide being released has caused the earths average temperature to increase
What do making bonds involve?
Atoms giving away, taking atoms or sharing electrons to make full outer shells
What is memory foam an example of?
A smart material, as its a polymer that gets softer as it gets warmer
Why is partial combustion bad?
Because soot, unburnt fuel and carbon monoxide (poisonous gas) are released
Why is crude oil bad for the environment?
Oil spills can happen as the oil is transported, birds get covered in it and are poisoned as they try to clean themselves, sea otters and whales are also poisoned, Also you have to burn the oil to release energy which can cause global warming, acid rain and global dimming
Why is this a good way to produce ethanol?
The raw material (sugar) is renewable and widely available and it can be a cheap way to make fuel in poorer countries that cant make petrol
What sort of bond do alkenes have?
They have a C=C bond - a double carbon carbon bond
How does a fractioning column work?
heated crude oil is piped in at the bottom, the vaporised oil rises up the column and the various fractions separate at different levels as they condense
What is crude oil?
A mixture of hydrocarbons
What is the formula for propene?
C3H6
Cooking food in any sort of oil makes the food more _________?
Fattening
What happens to the ions when they gain or lose electrons?
They become atoms or molecules and are released
What do the physical properties of a polymer depend on?
What its made from, polyamides are usually stronger than poly(ethene) and also the temperature and pressure of polymerisation
What is most iron converted into?
Steel (an alloy)
