What three particles are atoms made of and what are their charges?
Proton - positive, Neutron - no charge, Electron - negative
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What is the displayed formulae for the following: Carbon Dioxide
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What are emulsifiers used for?
Mixing oil and water in foods
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Describe the features of an emulsifier molecule and how they work
Hydrophilic head binds to water molecules and hydrophobic tail binds to oil molecules to fix the two together
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Why are some foods cooked?
To change the chemical state in order to improve taste, texture, digestibility etc.
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What happens to protein molecules when they are cooked?
They denature and change shape which is irreversible
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What kind of chemical change does baking powder undergo during cooking?
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Give the word equation for this process
Sodium hydrogencarbonate --> Sodium carbonate + Carbon dioxide +Water
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And the symbol equaion
2NaHCO3 --> Na2CO3 + CO2 + H2O
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Which of the products makes a cake rise? How?
Carbon dioxide forms bubble in the cake expanding the substance
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How could you prove that the gas released by thermal decomposition of baking powder is Carbon dioxide?
Heat some NaHCO3 and use a tube to bubble the gas produced through lime water. If it turns cloudy it's CO2
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What component of a perfume gives it its specific properties?
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What properties must a perfume have?
High volatility, non-irritant, insoluble in water, non-toxic and doesn't react with water
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What is needed for esterification?
A Carboxylic acid and an alcohol plus an acid catalyst (usually concentrated Sulfuric acid)
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What are the products of Esterification?
Ester and water
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Why are perfumes and cosmetics tested on animals and why is it controversial?
To make sure they're safe for human use. Some argue that it is cruel and unnecessary
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Why do substances change state when heated?
Particles gain kinetic energy and overcome the intermolecular forces between them so they start to move around more changing the state
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How do we smell things and why are some substances more potent than others?
Fast moving particles near the surface of liquids can overcome attractions and leave the substance, these reach receptors in the nose and so we smell it. Some substances' particles have weaker forces and so overcome them more quickly - more volatile.
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What is a solution?
Mixture of a solute and a solvent that doesn't separate out
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What is a solute?
The substance being dissolved
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The liquid it's dissolving into
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Means something will dissolve (not necessarily in water)
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Will not dissolve at all
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A measure of how much it will dissolve and how easily
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Why is nail varnish insoluble in water?
Because the attraction between nail varnish molecules are stronger than the attractions between a nail varnish and a water molecule so they never bond with each other
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Why is nail varnish soluble in acetone?
Because the attractions between the molecules of the two substances are stronger than the ones holding them together
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What does the solubility of a substance depend on?
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What gives a paint its colour?
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What is a colloid?
Tiny particles dispersed in a substance so they don't settle but are not dissolved in it
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What are the components of an emulsion paint?
Water (solvent), pigment and binding medium
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How does emulsion paint dry?
The water solvent evaporates leaving the binding medium and pigment behind as a solid layer
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Why are emulsions suitable for painting walls indoors?
Because they don't give off harmful fumes and are fast-drying
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What are the components of a gloss paint?
Organic compound that disolves oil (solvent), oil (binding medium) and pigment
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How do oil-based paints dry?
The solvent evaporates leaving the oil to be oxidised by the air turning it into a solid layer with the pigment. This means it takes longer to dry
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What makes oil-based paints more suitable for outdoor use?
When dry, they are glossy, waterproof and hard-wearing and also they can produce harmful fumes depending on the solvent
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What is a thermochromic pigment?
A paint that changes colour depending on the temperature
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List three uses of thermochromic pigments
Baby utensils (to indicate when food is the right temperature), kettles and novelty items
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What is a phosphorescent pigment?
Pigment that absorbs light, stores it and then emits it back out as light energy over a period of time
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List three uses of phosphorescent pigments
Emergency lighting, glow in the dark watch hands and novelty items
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Why are phosphorescent pigments used in watches today instead of previous methods?
Radioactive paints used to be used as they glowed constantly without needing light input but they were found to be unsafe so phosphorescents are now used
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What is a monomer?
Single, small, unsaturated molecules
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What is a polymer?
A chain of monomers joined together to form one long saturated molecule
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What conditions are necessary for polymerisation?
High pressure and a catalyst
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How do monomers form polymers in addition polymerisation?
The double covalent bonds break and join together to string the molecules together
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What polymer is made from Chloroethene?
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What dictates the properties of a polymer?
The intermolecular forces between the polymer chains
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What properties will a plastic with strong intermolecular forces have?
High melting point, durable, rigid
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What properties will a plastic with weak intermolecular forces have?
Low melting point, 'stretchy', weak
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Why does it have these properties?
The polymer chains can slide over each other
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What is low density polyethene commonly used for?
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Nylon is a synthetic polymer used often in clothes, is it waterproof?
No, not on its own
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What is it coated with to make it waterproof?
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What advantage does GoreTex have over traditional waterproof clothing?
It lets water vapour out so sweat doesn't build up
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Why are plastics difficult to dispose of?
Most of them aren't biodegradable
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Define a hydrocarbon
A compound that contains hydrogen and carbon atoms ONLY
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List three commercially used hydrocarbons
Petrol, diesel, ethane, propane etc.
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How are atoms bonded in molecules?
Covalent bonds - atoms share electrons to complete their outer shells
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What is the difference between a double and single covalent bond?
In a double bond two electrons from each atom are shared, only one form each is shared in a single bond
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Alkanes have what kind of covalent bonds between their carbon atoms?
Single - this makes them saturated
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Double - this makes them unsaturated
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How can you test if a substance is an alkene?
Add bromine water - if it is an alkene the double bond breaks and the bromine attaches (addition reaction) which turns the liquid colourless
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What is the generic formula for an alkane?
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What is the generic formula for an alkene?
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Why do we heat crude oil in a fractional distillating column?
To separate all the different hydrocarbons into fractions that can be used for different purposes
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How are the fractions separated?
The column is heated form the bottom where the crude oil is put in. The different hydrocarbons have different intermolecualr forces due to size and so smaller molecules have lower boiling points. They evaporate and rise up the column, and exit
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Why do they exit at different places?
When the temperature is low enough for them to condense, they flow out. So smaller molecules come out the top.
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List the fractions (top to bottom) that exit the column
LPG, Petrol, Naptha, Kerosene, Diesel, Oil and Bitumen
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What properties do longer chain hydrocarbons have?
Higher melting point, less flammable, more viscous and less volatile
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What is Cracking?
Breaking large alkanes into smaller alkanes and an alkene
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Why is it done?
We don't get enough highly used hydrocarbons (like petrol) from fractional distillation but we get more of some (like bitumen) l]than we need. Cracking makes more of the useful stuff
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What conditions are needed for cracking?
High temperature (400 to 700 degrees Celsius) and a catalyst (Aluminium oxide powder)
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What political problems can oil cause?
Some countries could stockpile it to increase its value, when oil reserves start to run out we may have to reply on politically unstable countries for oil and terrorists can gain control of oil reserves
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What environmental problems can oil cause?
Oil spills damage sea-life as can the detergents used to get rid of them and oil can cover birds feathers
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List as many properites to consider when choosing the best fuel
Energy value/efficiency, availability, storage, cost, toxicity, ease of use, pollution
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What are the products of the complete combustion of a hydrocarbon?
Carbon dioxide and water (+energy)
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How can you test this?
Burn a hydrocarbon and draw the gases through a tube with a water pump. Surround one point of the tube with ice to condensate water and then bubble the gas through limewater to test for CO2
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What are the products of the incomplete combustion of a hydrocarbon?
Carbon dioxide + Water +Carbon monoxide (+energy)
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Why is incomplete combustion more dangerous and messy?
Carbon monoxide poisoning can be fatal and soot builds up
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What was the first phase of atmospheric evolution?
Volcanoes releasing CO2 and steam
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What was the second phase?
Green plants evolve and produce oxygen as the CO2 is taken out of the atmosphere and put into sedimentary rocks. N2 is also put into the air by ammonia reacting with oxygen and denitrifying bacteria breaking down nitrates
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And the third?
The Ozone layer formed as oxygen was bonded with itself by UV rays which blocked out dangerous rays allowing life to thrive
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Name the gases in the atmosphere and their amounts
Nitrogen (78%), Oxygen (21%) and Carbon dioxide (0.035%). There are also varying levels of water vapour and noble gases
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In the Carbon Cycle, what four processes put CO2 back into the atmosphere?
Respiration, decay, combustion and thermal decomposition of sedimentary rocks (chalk and limestone)
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What takes CO2 out of the atmosphere?
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How have humans affected the amount of CO2 in the atmosphere?
More people means more respiration and more resources being used such as burning fossil fuels. All of which puts CO2 into the atmosphere
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What causes acid rain?
Sulfur dioxide and oxides of nitrogen in the air produced by burning fossil fuels mix with clouds and fall as acidic rain
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What negative effects does acid rain have?
Water sources can become acidic and kill water-life, trees die, stone buildings and statues are destroyed and metal corrodes
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How do catalytic converters in cars help reduce air pollution?
A mixture of platinum and rhodium turns Carbon monoxide and Nitrogen oxide into Nitrogen and Carbon dioxide
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Give the balanced symbol equation for this process
2CO + 2NO --> N2 + 2CO2
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Other cards in this set
What is the displayed formulae for the following: Carbon Dioxide