1
Q
What are properties of transition metals?
A
Strong/hard Shiny Malleable Conduct heat and electricity High densities High melting and boiling points
2
Q
What are alkanes and what is their general formula?
A
Saturated hydrocarbons that poses similar chemical properties
-CnH2n + 2
3
Q
What are alkenes and what is there general formula?
A
Unsaturated hydrocarbons with a C=C bond
-general formula = CnH2n
4
Q
How do you test for alkenes?
A
Bromine addition reaction
- when shaken with bromine water, alkenes will grin the solution colourless as an addition reaction happens across the double bond
- alkanes will remain in a brown/orange solution
5
Q
How can hydrocarbons be oxidised?
A
Through burning them in a combustion reaction
-they produce carbon dioxide and water
6
Q
What is the herbal formula and functional group of alcohols?
A
CnH2n +1 OH
-OH functional group
7
Q
When oxidised, what do alcohols form?
A
Carboxylic acids
E.g. ethanol + oxidising agent = ethanoic acid
8
Q
What is the general formula and functional group of carboxylic acids?
A
Cn-1H2n-1 COOH
-COOH is the functional group
9
Q
What is addition polymerisation?
A
When lots of unsaturated monomers can open up their double bonds and join together to form polymer chains
-this process requires pressure and heat
10
Q
In addition polymerisation, where does the name and formula come from?
A
- name Comes from the monomer by placing brackets around it with poly in front of the bracket
- formula of the monomer goes in the brackets with n after
11
Q
What are the properties and uses of polyethene?
A
- flexible, electrical insulator, cheap
- plastic bags +bottles, wire insulation
12
Q
What are the properties and uses of polypropene?
A
Flexible, strong, tough, mouldable
-crates, furniture, ropes
13
Q
What are the properties and uses of polychloroethene?
A
Tough and cheap
-window frames and water pipes
14
Q
What are the properties and uses of polytetrofluroethene?
A
Unreactive, non stick, tough
-nonstick pans, waterproof clothing
15
Q
What does condensation polymerisation involve?
A
- two different types of monomers to form a polymer
- each monomer must contain at least two functional groups, one on each end
16
Q
What is lost during condensation polymerisation?
A
For each new bond formed a small molecule such as water is lost
17
Q
What does forming polyesters through condensation polymerisation involve?
A
- Formed when Di carboxylic acid monomers and Di alcohol monomers react, where both have two functional groups
- this forms an Ester link
- water molecule is eliminated (H from carboxylic acid and OH from the alcohol)
18
Q
What is an ester link?
A
C with a couple bonded O and single bonded O
19
Q
Why should we dispose of polymers properly?
A
As they are made from crude oil which is a finite resource so will become progressively more expensive as it runs out
20
Q
What are some negatives of landfill sites?
A
- valuable land is used and polluted
- there is only a finite amount of space
- destroys habitats
21
Q
What are some positives of landfill sites?
A
Can produce energy from waster
Non biodegradable so will sit there for years
22
Q
What are the positives and negatives of combusting polymers?
A
- produces lots of energy to generate electricity
- toxic gases may be released such as CO2which contributes to global warming and acid rain etc
23
Q
What are some advantages of recycling polymers?
A
- reduces the amount of non-biodegradable waste sent to landfill
- reduces emissions of greenhouse gases
- preserves finite crude oil
- saves money whilst creating jobs
24
Q
What are some negative of recycling polymers?
A
- must be thoroughly separated as otherwise it may ruin the quality of the plastic, this is time consuming
- can only be recycled a finite number of times or their strength decreases
- melting polymers still creates greenhouse gases
25
What does a chemical cell involve?
- in a displacement reaction, it is exothermic so the mixture gets warm
- in a chemical cell we can manipulate this so that we can convert chemical energy to electrical energy rather than heat
- e.g. in batteries
26
What two components do all chemical cells have?
- two separate metal electrodes dipped into a solution of one of their own salts
- a ‘salt bridge’ to allow dissolved ions to pass from one to another
27
How can you increase voltage in chemical cells?
Choosing materials further apart on the reactivity series
28
What is a fuel cell?
Hydrogen + oxygen = water
The water is created as hydrogen looses electrons to become positive ions and then reacts with oxygen in air to form water
29
What are the advantages of fuel cells/hydrogen cars?
- quieter so less noise pollution and require little maintenance so less operators are needed, hence reduced fares
- increased use of public transport so is economical
- more efficient as acts as a direct converter so less fuel is needed
- environmentally beneficial as only byproduct is water
30
What are disadvantages of hydrogen cars/ fuel cells?
- explosive so posses serious danger in am accident, this might make investment low so it won’t be profitable
- hard to store so must be kept in a reinforced pressurised container which is expensive
- at present, pit main source of manufacturing hydrogen is through reacting steam with fossil fuels which creates CO2 as a product
31
What are alloys?
Alloys are made by adding another element to a metal so the different sized atoms will upset the regular arrangement and layers, making them harder to slide so stronger and more useful
32
What are some reasons for making alloys?
-change the colour, increase strength/density, better castings, change the electrical and thermal properties, change resistance
33
Why is gold often alloyed?
Pure gold is relatively soft and wears away easily but other metals such as silver are added to enhance the strength or change the colour
34
What is corrosion?
- when materials can corrode in the presence of oxygen and water to form their metal oxides
- this is caused by REDOX reactions when the metal looses electrons whilst oxygen gains electrons
35
How does painting and oiling prevent/help corrosion?
- can act as a barrier to keep out water and oxygen whilst providing colour
- oiling has to be used when moving parts are involved
36
How does sacrificial protection prevent/help corrosion?
This involves placing a more reactive metal amongst the iron so that the base reacts with that metal instead of the main object
37
How does galvanising prevent/help corrosion?
A type of sacrificial protection
- place zinc within an iron object to prevent rusting as it is more reactive
- it also acts as a barrier in thing such as buckets or iron roofing
38
What is electroplating?
- Coating the surface of a metal with another metal using electrolysis
- the cathode is the object you are electroplating and the anode is the bar of metal you are using
- the electrolyte is a solution containing the ions of the metal your playing
39
Why do you electroplate?
- the metal used for protection is usually unreactive and doesn’t corrode easily
- used in cutlery and cooking utensil so they last longer
- used in jewellery/decorations to improve appearance
40
What properties and uses do metals have?
- Good at conducting heat and electricity
- high density, malleable and can form alloys
- often used in saucepans etc
41
What properties and uses do polymers have?
-very adaptable and flexible so can be moulded easily
-cheaper than other material but can degrade easily so can
be used for not very valuable things
-thermal and electrical, insulation
42
What properties to ceramic have and what is clay used for?
brittle and strong so are hard wearing
| -clay is easy to mould and is soft but can also be hardened using heat so is an ideal building material
43
What properties and uses does the ceramic, glass have?
Glass is transparent and strong but can also be moulded when is hot yet brittle when thin
-it is therefore less likely to corrode than clear plastic so is good for window pains
44
What properties and uses do composites have?
-made of more than 1 material embedded into another
-it’s properties are dependent on what it is made from so is useful as can be designed for specific purposes. E.g. carbon fibre is light and strong is ideal for aerospace and sports cars
-very expensive in comparison to other material
(Fibreglass and concrete)
45
What are the chemical properties of transition metals?
They form coloured compounds which are used to identify the transition metal in a substance
-they are used to catalyse reactions, e.g. iron is used in the haber process and iron chloride in the manufacturing of PVC
45
What are some uses of transition metals based off physical properties?
Gold is used in jewellery because its shine, malleable and corrosion resistant
- copper is used for electrical wires as conducts electricity and is ductile. It is also cheap so suitable for mass use
- may also be used for frying pans as can conduct heat and electricity
45
What is aluminium used for?
Overhead cables
- conducts electricity
- resistant to corrosion so can be exposed to the weather
- strong, cheap and less dense than copper so can hang in the air
45
Why are magnelium and brass alloyed?
- 95% aluminium,5% magnesium: makes it less dense and four times stronger than aluminium. It has better resistance to corrosion as well. Often used in cars and aeroplanes
- brass is used for lateral plug pins as copper is good at conducting electricity but is malleable- this stops it
45
Why is iron alloyed?
Iron on its own will rust fairly quickly but steel is much less likely to as it is alloyed with a small amount of carbon
-e.g. bridges, cutlery, washing machines
46
What is oxidation, tarnishing, corrosion and rusting?
- reaction with oxygen
- when a thin layer is formed over a metal that prevents further oxidation
- corrosion when a metal continues to be oxidised and becomes weak and starts to break
- Rustin is the corrosion of iron or steel
47
How can we prevent rusting?
- Removal of air by storing in an unreactive atmosphere
- removal of water by using descent powder to absorb water
- sacrificial protection when a more reactive metal is attached to iron so it is oxidised in its place protecting it
48
Why is the actual yield of a reaction usually less than the theoretical?
- incomplete reactions = if not all the reactants are converted to products
- practical losses = loosing some when transferring between containers e,g, left on side of containers
- unwanted reactions =unexpected reactions occur and can be due to impurities in the reactants or changes in reaction conditions
49
What is atom economy?
The percentage of the mass of reactants that has been converted to desired products
50
What are the factors influencing atom economy?
- reactions with low atoms economy use up resources quickly and make lots of water products which is expensive of dangerous
- this makes them usually not profitable
- you therefore must consider the percentage yield, the rate of reaction, the equilibrium position
- usefulness of by-products
51
Overall what reaction pathway do you choose?
Tend to go higher atom economy as it is harder to increase than percentage yield
52
What is avagadro’s law?
If the temperature and pressure of gases are the same,the same moles of different gases will occupy the same volume
-24dm3 or 24000cm3 at room temperature and pressure (RTP = 20p and 1 atmosphere
53
How do you calculate molar volume?
Molar volume = gas volume/ number of moles
54
What is the equation for Avagadro’s law?
Moles = volume/ 24
Chemistry
flashcards
Decks in class (12)
# Cards
-
Topic 8 - Fuels and Earth's Sciecne46
-
Core Practicals22
-
Qualitative Analysis19
-
Groups Of The Peridoic Table39
-
Structure And Bonding43
-
Extracting Metals And Electrolysis48
-
States of matter and mixtures48
-
Acids And Bases33
-
Seperate Chemistry60
-
The Perioic Table9
-
Triple Content58
-
Rates Of Reaction38
