Unit 1 Flashcards
Where are protons and neutrons found in the atom?
Nucleus
Where are electrons found in an atom?
They orbit the nucleus
What does the atomic number tell you?
The number of protons
What does the mass number show?
The number of protons and neutrons
What does the group number show?
The number of electrons in the outer shell
Why are noble gases unreactive?
They have a full outer shell
What is the general formula for the saturated compound?
CnH2n+2
What is the general formula for the unsaturated compound?
CnH2n
What is an isotope?
A number with the same amount of protons, different number of neutrons
What is the formula of alkanes?
CnH2n+2
What is the formula of alkenes?
CnH2n
What is the unsaturated compound?
CnH2n
What is the saturated compound?
CnH2n+2
What is the formula of calcium carbonate?
CaCO3
What is limestone also known as?
Calcium carbonate
Is calcium carbonate a compound or mixture?
It is a compound
What does calcium carbonate break down into through thermal decomposition?
Calcium oxide and carbon dioxide
What is heated in a kiln to make cement?
Clay and limestone
What is used to make mortar?
Cement, sand and water
What happens to limewater when carbon dioxide is present?
It turns cloudy
Calcium oxide reacts with water to create what?
Calcium hydroxide
How do you break down limestone?
Thermal decomposition
What colour is calcium oxide when it is hot?
Yellow
What colour is calcium oxide when cold?
White
How do you produce calcium oxide from calcium carbonate?
Thermal decomposition
What is the formula for calcium oxide with water?
CaO + H2O -> Ca(OH)2
What is a benefit of limestone quarrying?
Local employment
What is produced when Limestone is thermally decomposed?
Calcium oxide and carbon dioxide
Why is it difficult to thermally decompose elements in group 1 in class?
Bunsen burners cannot reach a high enough temperature
What is mixed with limestone and sodium carbonate to create glass?
Sand
Which two ways can calcium carbonate be reacted?
Calcium carbonate and with acids
What type of rock is limestone?
Sedimentary
How does limewater convert into limestone?
Carbon dioxide is bubbled through it
What compound dissolves in water to form limewater?
Calcium hydroxide
Carbonates react with acids to create what?
Carbon dioxide
What can calcium hydroxide be used for?
Neutralising acidic fields
How is concrete made?
Sand and aggregate
What are the negatives of limestone quarrying?
- Make the landscape ugly
- Processes cause loud noises
- Destroys habitats
- Transport causes pollution
What is a negative of cement factories?
They create lots of dust
How is limestone used in a power station chimney?
It neutralises the sulfur dioxide
Which is more reactive, sodium or potassium?
Potassium
What are the trends as you go down group 1?
- More reactive
- Lower melting point
- Lower boiling point
What are the characteristics of transition metals?
They are good conductors of heat and electricity
What is an ore?
A rock that contains enough metal to make it economic to extract the metal
How are more reactive metals extracted?
Electrolysis
How are less reactive metals extracted?
Reduction with carbon
How is copper purified?
Electrolysis
Why is copper useful for wiring?
It’s soft so easily bent and a good conductor of electricity
What makes copper useful for plumbing?
Its a good conductor of heat and doesn’t react with water
What is an alloy?
A mixture of two elements, usually metals
Why are alloys harder than pure metals?
They contain atoms of different sizes, which distort the regular arrangements of atoms, making it more difficult for layers to slide over one another
What do all alkali metals have in common?
They need to be stored in oil and handled with forceps
What determines whether an ore can be extracted by reduction?
Metals lower than carbon in the reactivity series must be extracted by reduction
What happens when an ore is reduced?
Oxygen is removed from it
What is a negative of electrolysis compared to reduction?
It is much more expensive as it uses more energy
What is usually the electrolyte in electrolysis?
A metal salt solution made from the ore e.g copper sulfate
Explain how copper is purified?
- Electrons are pulled off copper atoms at the anode, causing them to go into the solution as Cu2+ ions
- Cu2+ ions near the cathode gain electrons and turn back into copper atoms
- The impurities at the anode drop as sludge, whilst pure copper atoms bond to the cathode
Why is electrolysis used in the extraction of copper?
Smelting only gives an impure copper atom
How is copper extracted from a solution?
Displacement using a more reactive metal
What are the new methods of extracting copper ores?
Bioleaching and phytomining
What is bioleaching?
Bacteria are used to separate copper from copper sulfide. The solution produces from this process contains copper
What is the disadvantage of the new methods of extracting copper?
They are slower and produce less copper
Why is it important to recycle metals?
- They are finite
- Extracting new metals causes pollution
- Saves money due to using less energy
When is aluminium most useful?
As an alloy
What are properties of aluminium and titanium?
Corrosion resistant and low density
Why would aluminium be good for building an aeroplane?
Strong, malleable and light
What is a use of titanium?
As a hip replacement
What are some downfalls of metals?
- Some corrode when exposed to water and air
- If they corrode, they lose strength
- Metal fatigue
Which types of steel are made from iron?
- Low carbon steel (0.1% carbon)
- High carbon steel (1.5% carbon)
- Stainless steel (chromium added)
Why is crude oil called a fossil fuel?
Because it is formed from the remains of ancient sea creatures
Compared to large hydrocarbons, small hydrocarbons are…
More volatile
Is the top of an oil fractioning column warmer or colder than the bottom?
Colder
What happens to a liquid during its separation from a mixture by distillation?
Evaporation followed by condensation
Which fraction has the largest carbon chain?
Bitumen
What is a use of kerosene?
Aeroplane fuel
How do geologists find oil?
They study the rock structures
Which hydrocarbons are less efficient?
Those that have a longer chain
What is cracking?
When long hydrocarbon chains are converted into smaller hydrocarbon chains
What is a use of bitumen?
Tarmac
What is crude oil made up of?
Mostly alkanes
If a hydrocarbon molecule chain is shorter?
- It is less viscous
- It is more volatile
- It is more flammable
What does volatile mean?
More volatile means it turns into a gas at a lower temperature
What are the negative gases produced by fossil fuels?
Sulfur dioxide and carbon dioxide
What happens if partial combustion takes place?
Carbon monoxide and soot is released
How are sulfur dioxide emissions reduced?
The sulfur is removed before the fuel is burnt, or they are removed after combustion in power station by Aid Gas Scrubbers
What causes global dimming?
The soot that is released when fossil fuels are burnt
What is the result of global dimming?
Sunlight is reflected back into space
What are the alternate fuels being developed?
Ethanol, biodiesel and hydrogen gas
What are the positives of using hydrogen gas as a fuel?
It does not emit any harmful emissions
What are advantages of ethanol and biodiesel as fuels?
They are carbon neutral carbon neutral
What are negatives of ethanol as a fuel?
Engines need to be converted and it isn’t widely available
What are negatives of biodiesel?
It is expansive and we cant make enough to completely replace diesel
What does cryolite do in electrolysis?
Lowers the melting point so less energy needs to be used
What were the reasons for continental drift?
- Fossils in the wrong climate
- Matching fossils in different continents
- Jigsaw theory
Why didn’t some scientist accept Wegener’s theory?
- He was an astronomer
- He made incorrect calculations
- Insufficient evidence
What causes heat within the mantle?
Radioactive decay
What are the proportions of gases in the atmosphere?
80% Nitrogen
20% Oxygen
Small proportions of CO2, water vapour and noble gases
What was the earth like during its first 1 billion years?
Intense volcanic activity that released gases that formed the atmosphere and water vapour that cooled to become oceans
Which planets was the earths early atmosphere similar to?
Venus and Mars
What is the theory as to how life was formed?
There was an interaction between hydrocarbons, ammonia and lightning. There are also many others.
What is the primordial soup theory?
Billions of years ago, the atmosphere was made up of nitrogen, hydrogen, ammonia and methane. Lightning struck, causing a chemical reaction, resulting in amino acids. The amino acids became a body of water out of which life eventually crawled (primordial soup).
Which gases are involved in the primordial soup theory?
Nitrogen
Hydrogen
Ammonia
Methane
What was the Miller - Urey experiment?
A closed experiment which tested the primordial soup theory
What were the results of the Miller - Urey experiment?
They found similar results but not exactly the same, leading to questions about the theory
Where did most of the carbon dioxide go from the atmosphere?
- Locked up in sedimentary rocks as fossil fuels
- Dissolved into the ocean
What is a negative of the ocean absorbing much of the atmospheres CO2?
It has had an impact on the marine environment
What is air?
A mixture of gases with different boiling points
Why is air fractionally distilled?
To provide a source of raw materials used in a variety of industrial processes
What is the structure in which fractional distillation occurs?
A fractionating column
What are the products of cracking?
Alkanes and alkenes
What is cracking?
The process which breaks down long-chain hydrocarbons into shorter, more useful hydrocarbons
What is the catalyst present when reacting ethene with steam to create ethanol?
Phosphoric acid
During ferementation, sugar is converted into what?
Ethanol and carbon dioxide
What is polymerisation?
When many monomer join together to form polymers
Plastics are an example of what type of polymers?
Synthetic polymers
What is added to a plastic bag to make it biodegradable?
Cornstarch
Are polymers saturated with single bonds or unsaturated with double bonds?
Saturated with single bonds
What does biodegradeable mean?
They are not broken down by micro organisms
What are many polymers made from?
Fossil fuels
What is the molecular formula for ethanol?
C2H5OH
Why is ethanol not a hydrocarbon?
Because it contains oxygen as well as hydrogen and carbon
Which two ways can you make ethanol?
Fermentation of a sugar solution and hydration
What is a continuous process?
Reactants are constantly being put into the reaction vessel, and products are always being taken out
What is a batch process?
The reaction vessel must be emptied and cleaned when the reaction is complete
What is the name of the process when seeds are crushed and then the crushed material is squeezed to form oil?
Pressing
How can oil that has been extracted by distillation be refined?
By removing water and other impurities
Where do biodiesels come from?
Plants which have had their oil extracted
Why do chemists crack oil?
To get the more useful materials out of the oil
What type of reaction is cracking?
Thermal decomposition
Do alkanes or alkenes have a C=C double bond?
Alkenes
Describe cracking?
- Heat and vaporise the long chain hydrocarbon
- Pass vapour over a powdered catalyst between 400-700 degrees celcius
- Aluminium oxide is the catalyst used
- The long chain molecules then split on the surface of the catalyst
What are the 3 methods for extracting plant oils?
Cold pressing
- Steam distillation
- Solvent extraction
What is the highest temperature oils can be extracted using cold pressing?
50 degrees celcius
What are advantages of steam distillation?
- Efficient
- Due to the use of water, a byproduct can be created to sell
What physical state is saturated fat at room temperature?
Solid, it also has only C-C single bonds
What physical state is unsaturated fat at room temperature?
Liquid, it has double bonds C=C
What conditions are needed for hardening oil?
60 degrees, hydrogen and a nickel catalyst
How does hydrogenation harden vegetable oil?
The C=C in unsaturated oil breaks open and joins with the hydrogen, to give only C-C bonds and forms unsaturated oil
Why is oil better at cooking some foods than using water?
It has a higher boiling point, so the food can be cooked at a higher temperature and will cook quicker
Why do unsaturated fats have a lower boiling point?
They have C=C bonds, which means that they cannot rotate as easily, and have smaller intermolecular forces which means they need less energy to change state
What is an emulsion?
A mixture of small globules of one liquid suspended in another that are immiscible because they will not mix
Why do you use detergent to wash dishes?
It is an emulsifier that allows the emulsion of fat molecules and water molecules to mix up and wash them off the plate
What does immiscible mean?
Does not mix or combine
What are hydrogenated vegetable oils used for?
Baking and cooking
What are the features of an emulsifier?
- Small hydrophilic head
- Long hydrophobic tail
How many different elements are there?
About 100
Why is helium different from other noble gases?
It still has a full outer shell, but only has 2 electrons in this shell
Why is the mass of products always equal to the mass of reactants?
No atoms are lost or made during a chemical reaction
What is formed when a carbonate reacts with an acid?
Carbon dioxide, salt and water
How can copper be extracted from copper-rich ores?
Smelting in a furnace
What is a blast furnace made up of?
96% iron
Why is iron used in a blast furnace?
It stays strong during compression
How are oxides of nitrogen formed?
At high temperatures
How do alkenes react with bromine water?
Turn it from orange to colourless
How do alkanes react with bromine water?
Stays orange (no reaction)
What are the new uses for polymers?
- Hydrogels
- Waterproof coatings
- dental polymers
What is equation to show the fermentation of sugar?
Sugar -> CO2 + Ethanol
Why are vegetable oils very important?
- They provide a lot of energy
- They provide nutrients
What is the main reason that vegetable oils are used?
-Increases the energy that the food releases when it is eaten
What is the viscosity of an emulsion?
Thicker than oil
How can ethanol be produced?
Hydration of ethene with steam in the presence of a catalyst
Fermentation with yeast
Why are vegetable oils important fuels?
They provide lots of energy
Why are vegetable oils important foods?
They provide lots of energy and nutrients
Are vegetable oils saturated or unsaturated?
Unsaturated
What catalyst is used to harden vegetable oils?
Nickel
What conditions are needed to harden vegetable oils?
60°c
Why can’t aluminium and titanium be extractes from their oxides with carbon?
It’s too expensive
Why is too expensive to extract aluminium and titanium?
There are too many stages in the process and large amounts of energy are needed
Why do most metals to require chemical reactions to extract them?
Because they are mostly found in compounds
What is a leachate?
The solution that is produced by the process of bioleaching
It contains copper
What is the process called when copper ore is heated in a furnace?
Smelting
What is phytomining?
Growing plants in copper rich soils
Why does copper build up in the leaves of plants?
Because it doesn’t use or get of the metal
What happens after plants are harvested in phytomining?
They are burnt in a furnace and then the copper is collected from the ash
How is CO2 removed from the atmosphere?
- Plants photosynthesizing
- Dissolved in oceans
- Locked up in sedimentary rock
How is CO2 added to the atmosphere?
- Plants and animals dying
- Fossil fuels burning
- Living things respiring
What is the composition of the mantle?
Solid but able to move slowly
What produced the oxygen that is now in the atmosphere?
Plants and algae by photosynthesis
How was limestone formed?
From the shells and skeletons of marine organisms
What is an industrial use of air?
It can be fractionally distilled to provide a source of raw materials
What happened when the earth cooled?
Water vapour in the air condensed into oceans
What is the emulsifiers effect on food?
- Improve texture
- Improve taste
- Encourages us to eat more high fat foods
Which type of fat is better for the health?
Unsaturated
How do emulsifiers keep liquids mixed?
The hydrophobic parts of the emulsifier go into small oil droplets, so each droplet is surrounded by the hydrophillic (water)parts. This keeps each oil droplet apart and the mixture together.
What are two advantages of cooking with vegetable oil?
- Quicker coooking
- Releases more energy when food is eaten
What are the advantages of hydrogenated oils being solid at room temperature?
They can be used as spreads and to make pastries which require solid fats
What is hydration?
The reaction of ethene with steam at a high temperature in the presence of phosphoric acid to create ethanol
What are the advantages of using fermentation to create ethanol?
- It is a renewable resource
- It is done at room temperature
What are the disadvantages of using fermentation to create ethanol?
- It produces an impure solution of ethanol
- It is a long process as it has to be done in batches
What are the advantages of using hydration to create ethanol?
- Produces pure ethanol
- It is a continuous process
What are the disadvantages of using hydration to create ethanol?
- It is non renewable
- Requires a high amount of energy
How is ethanol produced by fermentation?
The enzymes in yeast cause plant sugar to convert into ethanoland carbon dioxide
What is the formula of ethanol?
C2H5OH
What is a smart polymer?
A polymer which changes in response to changes in the environment
What is a biofuels?
A fuel made from animal or plant products
What is produced when fuels are burned in extreme conditions?
Nitrogen oxides
How is iron made from iron oxide?
It is reduced in a blast furnace
What does the boiling point of a hydrocarbon depend on?
The size of its molecule - The larger the molecule, the higher the boiling point
How do group 1 metals react with water and air?
They all react vigorously with both
Which is the only noble gas without 8 electrons in its outer shell?
Helium - it only has 2 electrons in its 1 shell
What is limestone needed for?
Building
What are the uses of blast furnace iron?
Used as cast iron because of its strength in compression
What are the products of complete combustion of hydrogen?
- Water
- CO2
What are the products of incomplete combustion of hydrogen?
- Water
- Carbon monoxide
Copper sulfate + iron -> ?
Iron sulfate + copper
Why does iron straight from a blast furnace make it have limited uses?
The impurities make it brittle
Why are alloys harder than pure metals?
The mixed size of atoms make the layers harder to slide over eachother
Pro’s of using ethanol as a fuel?
It produces very little pollution
A renewable resource
Con’s of using ethanol as a fuel?
Engines need to be converted before they will work with ethanol fuels
It isn’t widely available
Why are there worries about an increase demand for ethanol fuel?
Farmers will switch to growing crops for ethanol rather than food crops which will increase food prices
Pro’s of using hydrogen gas a fuel?
It is clean and renewable
How is hydrogen extracted?
Electrolysis of water
Con’s of using hydrogen gas as a fuel?
You need an expensive engine to be able to run on it
It is hard to store
What are three environmental impacts of burning hydrocarbons?
Encouraging global warming
Acid rain from sulfur dioxide release
Global dimming as soot and ash reflect sunlight back into space
What are benefits of using biodiesel?
Its carbon neutral
Engines don’t need to be converted
Produces less sulfur dioxide
What are some drawbacks/risks of using biodiesel?
We can’t make enough to completely replace diesel
It can improve food prices (same reason as ethanol)
What happens to carbon and hydrogen when they are combusted?
They are oxidised
What are the two different methods of cracking?
Passing vaporised hydrocarbon over a hot catalyst
Mix the vaporised hydrocarbon with steam at a very high temperature
What is the catalyst used in cracking?
Aluminium oxide
What is the catalyst used for hydration of ethene to get ethanol?
HEATED phosphoric acid
What are the advantages of using emulsifiers?
They give food a longer shelf life
They allow food companies to produce food that is lower in fat but still has good texture
What is a disadvantage of using emulsifiers in food?
People can be allergic to them, like egg yolks which are commonly used
