Paper 2 Flashcards
What are the Alkali Metals?
Metals in Group 1 of the periodic table, that all contain one electron on the outer shell (Group ‘1’) and all share similar chemical properties
Name some of the physical properties of Group 1
Group 1 (Alkali Metals)
- Low Density
-Very Soft (can cut with a knife)
-Low m.p/b.p
-Good electricity/heat conductors
The Alkali Metals (Group 1) react (1.) ___________ with water, the products of this reaction are (2.) ____________ ____ and a (3.)____________ of that metal.
- Vigorously
- Hydrogen Gas
- Hydroxide
E.g. reaction with sodium and water:
Sodium + Water -> Sodium Hydroxide + Hydrogen
The Alkali Metals React also react with (1.) _______ to produce a (2.) ________ and (3.) ____________ _____
- Acids
- Salt
- Hydrogen Gas
What’s the Test for Chlorine?
Holding damp blue litmus paper over chlorine gas and see if it bleaches (turns the paper white)
What’s the Test for oxygen
A glowing splint will relight in the presence of oxygen
What is Group 7 called?
The Halogens
The Halogens exist as Diatomic Molecules; what does this mean?
They share one pair of electrons in a covalent bond to achieve a full outer shell on both
The Melting/Boiling Point of the Halogens (1.) ___________
As you move down the group, however the reactivity will (2.) ___________.
- Increase
- Decrease
^This is because as you move you the group the atomic radius of each element gets larger, so the electromagnetic force (force to pull in electrons) becomes weaker
What is a Halide?
When a Halogen gains an electron to form a 1- ion (ionic compound).
E.g. - Fluorine to Fluoride
- Bromine to Bromide etc
Free Card
More Reactive Halogens will always displace less reactive ones (Displacement Reactions).
As you move down Group 0 (Noble Gases), what properties increase?
-Boiling Point
-Melting Point
-Density
Give some properties of the Noble Gases
-Colourless Gas
-Monatomic (single atoms, no molecules)
-Inert
-Non-flammable
The noble gases are Inert - why?
The noble gases are inert because they all have full outer shells (stable electronic structure) so they don’t gain/lose electrons easily
What does Rate of Reaction mean?
How fast the reaction happens
How can you find the Rates of Reactions?
By measuring how quickly reactants are used up or how quickly the products are formed
Catalysts are substances that increase the rate of reaction without being used in the process. How do they work?
Catalysts provide an alternate reaction pathway that decreases the Activation Energy (therefore speeding up the process??)
What is Activation Energy?
The minimum amount of energy that reactant particles need when they collide in order to react.
What are Alcohols?
A Homologous series that organic compounds with a functional group -OH
Give the first 4 Alcohols
Methanol - CH3OH
Ethanol - C2H5OH
Propanol - C3H7OH
Butanol - C4H9OH
What is the general Formula of Alcohol?
CnH2n+1OH
What is the Atmosphere?
A layer/layers of gases surrounding a planet
What are the phases if the atmosphere forming?
Phase 1 - volcanos give out steam and CO2
Phase 2 - green plants evolved and produced oxygen.
Phase 3 - Rocks like iron oxide started to form, the oxidisation from this increased oxygen in the atmosphere. The ozone layer allowed the evolution of complex animals
What is a Greenhouse Gas/GG?
Gases in the earths atmosphere that trap the suns heat and energy
Describe the Green Effect and How it affects Global Temperature
- The Sun emits short-wavelength radiation and passes through the earths atmosphere (GG don’t absorb it)
- Thermal Radiation/Short-wavelength reaches the earths surface and is reflected as Long-WaveLength Radiation.
- Longwave Radiation is then absorbed by GG in the atmosphere
- GG then re-radiate it in all directions (including towards Earth).
- The Longwave-radiation is Thermal Radiation, it warms the surface of the earth.
Carbon is a very useful element for making large compounds, why?
Because each carbon atom can form 4 other strong bonds.
What is an Alkane?
Alkanes are a group of saturated hydrocarbons (which means they only contain single bonds between C atoms)
What is the Aklane General Formula?
CnH2n+2
Give some properties of Alkanes
(Hint: It’s about chain-length)
The shorter the Alkane’s chain-length:
• Lower the B.P
• The more volatile (evaporates more easily)
• Less Viscosity
• More Flammable
- What is an Alkene?
- What is the Alkene general formula?
- An Alkene is an unsaturated hydrocarbon that contains at least one Carbon-Carbon double bond (C=C).
- CnH2n
- What is Complete Combustion?
- What is the Word Equation for Complete
Combustion?
- Combustion (of hydrocarbons??) when oxygen is present.
- Hydrocarbon + Oxyegn -> Carbon Dioxide + Water
Why are Alkenes more reactive than Alkanes?
Because Alkenes are unsaturated; they have a double bond that can open up into single bonds, meaning they can react with other molecules.
Give the test for Alkenes
Alkenes are more reactive than Alkanes, so if you add bromine water to a solution of Alkenes, then the solution would turn from orange to colourless
What is a Polymer?
A long-chain molecule that is formed by lots of smaller molecules/units called ‘monomers’ joining together
- What are the two conditions needed for polymerisation?
- Give one use of polymers
- ‘Pressure’ and ‘Catalyst’
- Plastic Bags (Ployethene)
What does the Ester Link look like
O
| |
C — O
What is Condensation Polymerisation?
Condensation Polymers are when two different monomers are linked together with the removal of a small molecule, usually water.
Give one example of a Condensation Polymer
Polyester
Give the Pros and Cons of recycling
PROS
-Reduces Landfill
-Reduces toxic/greenhouse gas emissions
-Reduces Crude Oil Use (that’s needed to produce more plastics)
CONS
-Must be separated first (otherwise outcome’s quality/strength will be reduced
-Melting Polymers can produce harmful gases
Give a Pro and Con of Combustion (for the disposal of Polymers)
Pro - Can generate electricity
Con - if not carefully controlled, can produce toxic gases e.g CO2 (that contributes to global warming).
Why are Landfill sites used and why are they bad?
Landfill sites are used when polymers are too difficult/expensive to separate; they are bad because it uses a lot of valuable land and most products aren’t biodegradable
Why has carbon dioxide increased over the last 150 years?
Human Activity
Increase population mean more energy for lighting, heating, transport, gadgets etc
From what source does the increased energy consumption come from?
Fossil fuels
Other than the burning of fossil fuels, name another reason why carbon dioxide levels are increasing?
Deforestation
What impact does livestock farming have on climate change?
More people means more livestock (cows, goats etc). They produce methane - greenhouse gas. Whilst the levels are smaller than carbon dioxide, methane is a super effective greenhouse gas.
Is there scientific consensus that extra greenhouse gases from human activity have caused the average temperature of the earth to increase?
Yes
Global warming is a type of climate change that causes other types of climate change. Name some of these?
1) changes in rainfall patterns
2) flooding
3) Drought
Why is historical data less accurate than current records?
It’s was captured and fewer locations with older equipment, so it’s less representative
How can we use less fossil fuels?
Walking,
Cycling
Public transport
Being energy efficient
Government giving financial incentives to companies to do the same
Use renewable energy
Shortest/Longest Hydrocarbons are the most Un-Flammable/Flammable and so they make the worst/best fuels
Shortest
Flammable
Best
What is complete combustion?
It’s combustion where there’s lots of oxygen and the only products are carbon dioxide and water.
What is incomplete combustion?
When there’s not enough oxygen, incomplete combustion produces carbon monoxide, toxic gas and carbon in the form of soot.
Why is carbon monoxide dangerous?
It can combine with red blood cells and stop your blood from doing its proper job of carrying oxygen around the body. It’s also colourless and odourless
What can happen if you have carbon monoxide poisoning?
1 - fainting
2 - Coma
3 - death
During incomplete combustion, tiny particles of carbon can be released into the atmosphere and fall back to the ground (soot). Why is this problematic,
1 - makes buildings look dirty
2 - causes respiratory problems
How is sulphur dioxide formed?
Sulfur impurities released when fossil fuels are burned oxidise and become sulphur dioxide
What happens when sulphur dioxide mixes with clouds?
It forms sulfuric acid, which then falls as acid rain
Why is acid rain problematic?
1- erodes building
2- corrodes metals
3- Damages plants, either by landing on them or making the soil become acidic, affecting their growth
How is nitrogen oxide created?
It’s a reaction between nitrogen and oxygen in the air, caused by the energy released by combustion reasons
Why doesn’t a nitrogen oxide reaction usually happen?
It requires really high temperatures
True or False - Hydrogen can be used as a clean, renewable fuel?
True
In a hydrogen fuel cell, hydrogen combines with oxygen to produce energy. Are there any waste products?
Yes, water. Nothing else
What are some of the disadvantages of hydrogen?
1- a special, expensive engine is required
2-hydrogen gas needs to be manufactured and used energy from other sources, and this energy often comes from fossil fuels.
3- it’s hard store
Give the Common Properties of Alcohols
• Flammable
• Soluble
• Can be oxidised to make Carboxylic Acids ⭐️
Give the Process of Fermentation
Fermentation is a process that’s used to make a solution of Ethanol
- Mix yeast + carbohydrate solution (e.g. glucose) and seal in a warm environment.
- Happens fastest at 30-40 degrees. Lower: reactions slows. Higher: enzymes denature, reaction stops
- No oxygen present; otherwise eth is oxidised to ethanoic acid (what you get in vinegar).
- Reaction stops when Alc reaches 10%-20% bc it kills the yeast.
- Yeast falls to the bottom, eth solution at top.
How do you make a stronger/more concentrated solution of alcohol?
Use Fractional Distillation: dilute ethanol solution is heated, evaporated and condensed then collected in beaker; water is left as liquid as Eth has a lower b.p than water
What is a Nanoparticle?
A particle with a size between 1 and 100 nanometres (only containing a few hundred atoms)
Nanoparticles have a high…what?
Surface Area to Volume Ratio
Give and Explain 4 uses of Nanoparticles
• Catalysts - Nanos have a large SA, which means less material is needed for catalyst (less expensive + increases rate of reaction)
• Nanomedicine - Fullerenes (Nanos) are so tiny that scientists hope they can deliver dirge directly inside cells
• Electricity - Nanos can conduct electricity, meaning they can be used to make computer chips.
• Silver Nanoparticles - can be infused in surgical masks, wound dressings and sports wear due to antibacterial properties
Give some Disadvantages of Nanoparticles
• Relativley new, so effects of bodies not fully understood
• If washed into the ocean, it could affect the environment in ways we don’t understand
Explain the Advantages and Disadvantages of Nanoparticles in Suncream
Suncream with Nanos is more effective as the surface area provides more coverage from UV rays, however we are hot sure if they can get into our bodies and damage our cells
Give the types of materials
• Polymers - can be strong rigid (water pipes) light stretchy (plastic bottles, low density) heat resistant polymers (kettles)
• Ceramics - Clay (formed by decompiled rock, can be hardened when baked at high temps) Glass (heating limestone, sand and sodium carbonate until melted and malleable when hot)
• Composites (made from different materials. Properties depend on what’s it’s made from e.g. carbon fibre.
• Metals - Good at conducting heat and electricity. Normally would have high density and malleable. Can be mixed with other elements to form Alloys.
What are Alkenes?
Unsaturated Hydrocarbons, meaning they contain a double bond (reactive).
What are Alkanes
Saturated Hydrocarbons, meaning they have single bonds only (unreactive)
Why are Alkanes Unreactive?
Alkanes are Saturated Hydrocarbons, meaning they only contain single bonds. These single bonds between C and H are covalent bonds, so they are very strong and take huge amounts of heat and energy to break. Therefore, they do not easily reactive with other molecules
