C1 Flashcards

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What are the four main types of food additive?
Emulsifiers, colourings, flavour enhancers, and antioxidants.
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What is an emulsifier?
An emulsifier is a food additive which prevents oil and water from separating out in a mixture.
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What are the parts of an emulsifier?
It has a hydrophobic head which attaches to oil and repels water. It also has a hydrophilic tail which attaches to water.
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What common foods contain emulsifiers?
Mayonnaise, ice-cream, and spreads.
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What ingredient in baking powder under goes thermal decomposition?
Sodium Hydrocarbonate
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What is the formula of Sodium Hydrocarbonate?
NaHCO3
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What is the word equation for the thermal decomposition of Sodium Hydrocarbonate?
Sodium Hydrocarbonate --> Sodium Carbonate + Carbon Dioxide + Water
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What is the symbol equation for the thermal decomposition of Sodium Hydrocarbonate?
2NaHCO3 --> Na2CO3 + CO2 + H2O
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How does the thermal decomposition of Sodium Hydrocarbonate make cakes rise?
The Carbon Dioxide produced in the thermal decomposition cause cakes to rise.
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What are four purposes of cooking foods?
Destroys poisons, kills microbes, makes food easier to digest, and improves taste and texture.
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What happens when eggs and meats are cooked?
The protein denatures which breaks some of the bonds which makes the food more edible. It is irreversible.
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What happens when potatoes are cooked?
It ruptures the cellulose wall (which is indigestible) and causes the starch to swell and spread. This makes it more edible and digestible.
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What is an ester?
A substance with a pleasant smell. They are used in perfumes and are natural or artificial.
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What is the word equation for making esters?
Acid + Alcohol --> Ester + Water
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What are the properties of an ester?
Easily evaporates, non-toxic, non-reactive with water, non-irritant, and insoluble in water.
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Describe and explain volatility.
Volatility is a measure of how easy it is for particles to evaporate from a liquid. The particles gain energy and vibrate. They attempt to overcome the forces of attraction within the liquid. The particles are smelt when they evaporate.
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What is a solution?
A mixture of a solute and solvent which do not separate out.
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What is a solute?
A substance which is dissolved.
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What is a solvent?
A substance which a solute dissolves in.
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Define (in)soluble.
Means whether or not a substance can be dissolved.
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Define solubility.
A measure of how much a substance will dissolve.
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Why will nail varnish not dissolve in water but will dissolve in acetone?
The attraction between the nail varnish particles is greater than the attraction of the water particles and nail varnish particles. In acetone, the attraction between acetone and nail varnish particles is greater.
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What is a colloid?
It is where tiny particles of a solid are dispersed - but not dissolved - in a substance.
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How do oil paints dry?
The solvent evaporates which leaves behind the oil. The oil is then oxidised to leave behind a thin layer of solid.
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How do phosphorescent pigments work?
They absorb light and store it as energy. This energy is then released as light over time.
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What is a thermochromic pigment?
They are pigments which change colour based on their temperature.
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What is a monomer?
A monomer is an unsaturated hydrocarbon with a double bond between carbon atoms (they are alkenes).
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Describe addition polymerisation.
Monomers are passed over a catalyst with high pressure. This causes the double bond between the carbons in the monomers to break and join together with other monomers to form a polymer.
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What is the polymer formed by the monomer propene?
Polypropene
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Why are some polymers strong, rigid and have high melting points?
Some polymers have strong covalent bonds between chains or have cross-linking 'bridges' which cause a strong, rigid structure (difficult to move) and a high melting point as it takes more energy to break the bonds.
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What are some problems caused by polymers?
Many polymers are non-biodegradable which causes issues in the environment because they are dumped in landfills or litters which harms wildlife. Also, they are difficult to recycle because burning them usually releases toxic gases.
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What are some uses of fossil fuels?
Plastics, paints, energy, transport, power, and heating etc.
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What is the difference between an alkane and alkene?
Alkenes have a double bond between carbon atoms (they are unsaturated) whereas alkanes are saturated and don't have double bonds.
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What is the general formula for an alkene?
C(n)H(2n) where n is an integer greater than 1. For example C2H4 (ethene)
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What is the general formula for an alkane?
C(n)H(2n+2) where n is an integer greater than 1. For example, CH4 (methane)
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Describe the reaction between bromine water and hydrocarbons (alkanes and alkenes)
Reacting bromine water with alkenes will cause the bright orange bromine water to turn colourless as the double bonds are used to react with the bromine. Alkanes do not react so the bromine water stays bright orange.
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How does the number of carbon atoms affect the properties of hydrocarbons?
More carbon atoms cause a higher boiling point, make the substance less flammable, more viscous and less volatile.
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Describe fractional distillation.
Crude oil is heated so that most of it is vapourised, it is then fed into a fractionating column which is cooler further up the column. As the gas rises, it cools and each boiling point then separates out as they condense at different temperatures.
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What is cracking?
It is splitting longer chain hydrocarbons into shorter chain hydrocarbons which are often more useful.
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What is the purpose of cracking?
It is to split longer chain hydrocarbons into more useful shorter chains in order to meet demand based on supply of each hydrocarbon.
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What catalyst is used in cracking?
Aluminium Oxide
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What conditions are needed for cracking?
High temperature (400 to 700 degrees Celsius) and a catalyst of aluminium oxide.
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What is the word equation of cracking?
Hydrocarbon --> Shorter Length Hydrocarbon + Alkene (+ Potentially other products based on reactant hydrocarbon)
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What factors affect selecting fuels?
Energy value, availability, ease of storage, toxicity, pollution, ease of use, and cost.
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Why is ease of use an important factor for selecting fuel?
Some fuels are easier to ignite than others which can be important. For example, LPG is easily flammable so it is suitable for cooking whereas bitumen is difficult to ignite so it is difficult to use.
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What is the difference between complete and incomplete combustion?
Incomplete combustion produces carbon monoxide whereas complete combustion does not.
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What is the word equation for complete combustion?
Hydrocarbon + Oxygen --> Carbon Dioxide + Water
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How can carbon dioxide be tested for?
Bubbling it through limewater will turn the limewater cloudy.
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Why is carbon monoxide dangerous?
It is an odourless and colourless gas which attaches to haemoglobin preventing oxygen from binding to it. This effective suffocates a person from the inside. It is very dangerous as it is difficult to detect without a sensor.
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What causes acid rain?
Sulphur dioxide and nitrogen oxides combine with water to produce acid rain.
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Why is acid rain dangerous to fish?
It changes the pH of water bodies which makes them acidic which kills the fish as they aren't adapted to the pH.
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What is a catalytic converter?
It is a platinum and rhodium catalyst placed on modern exhausts to convert nitrogen oxides into nitrogen and carbon dioxide. This prevents immediate danger at the cost of contributing further to global warming and climate change.
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What is photochemical smog?
It is a form of air pollution caused by sunlight reacting with nitrogen oxides. It can contribute to things such as asthma.
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Why must pollution be controlled?
It can cause health issues for people (such as asthma) and contributes to global warming and climate change. This will, in the long term, affect the planet and environment and make the conditions different on Earth.
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What is the composition of gases in the air?
78% Nitrogen, 21% Oxygen, 0.035% Carbon Dioxide, and the rest is water vapour and noble gases in small amounts.
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How has human activity affected carbon levels?
They have caused an increase in carbon levels because of energy demand (burning fossil fuels), burning trees for land and electronic waste.
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What is the carbon cycle?
It is the recycling of carbon in nature and human activity. Carbon is returned to the air, soil and organisms continuously.
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How did the atmosphere evolve?
Firstly, volcanoes released steam and carbon dioxide. This led to green plants evolving and therefore photosynthesis which produced oxygen. Then, the ozone layer formed allowing for complex life to evolve.
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Other cards in this set

Card 2

Front

What is an emulsifier?

Back

An emulsifier is a food additive which prevents oil and water from separating out in a mixture.

Card 3

Front

What are the parts of an emulsifier?

Back

Preview of the front of card 3

Card 4

Front

What common foods contain emulsifiers?

Back

Preview of the front of card 4

Card 5

Front

What ingredient in baking powder under goes thermal decomposition?

Back

Preview of the front of card 5
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