Chemistry C7

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  • Created by: Hannah
  • Created on: 19-06-13 16:40
The chemical industry synthesises chemicals on different scales. What chemicals are made on a large scale (bulk)?
Ammonia, sulfuric acid, sodium hydroxide, phosphoric acid
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The chemical industry synthesises chemicals on different scales. What chemicals are made on a small scale (fine)?
Drugs, food additives, fragrances
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Government have a duty to protect people and the environment. What do they control by imposing strict regulations?
Chemical processes, storage of chemicals, transportation of chemicals
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Following standard procedures, carrying out titrations, scaling up production, interpreting results and carrying out quality assurance are all requirements of what occupation?
A chemist
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What are the 5 stages of the production of useful chemicals?
Preparation of feedstocks (starting materials), synthesis, separation of products, handling of by-products and waste, monitoring purity
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The sustainability of a chemical process depends on 7 things. What are these?
The atom economy, the use of renewable feedstocks, energy inputs and outputs, health and safety risks, waste prevention, the environmental impact, social and economic benefits
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What is atom economy?
A measure of the amount of reactants that end up as useful products
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How can the atom economy be calculated?
(mass of atoms in the useful product ÷ total mass of atoms in the reactants) x 100
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How can the percentage yield be calculated?
(actual yield ÷ theoretical yield) x 100
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Name 3 social benefits of green chemistry
Cleaner air quality, cleaner buildings, improved water quality in rivers and lakes
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What reduce the activation energy needed for a reaction, so the process is faster and can take place at a lower temperature?
Catalysts
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What remain unchanged and can be used again and again, so the process is more sustainable?
Catalysts
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What type of bonds do alkanes contain?
Single carbon-carbon bonds
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Are alkanes saturated or unsaturated?
saturated
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Are alkanes reactive?
No, they are unreactive
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What type of bonds do alkenes contain?
Double carbon=carbon bonds
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Are alkenes saturated or unsaturated?
unsaturated
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Are alkenes reactive?
Yes
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What is the name of the alkane CH4?
Methane
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What is the name of the alkane C2H6?
Ethane
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What is the name of the alkane C3H8?
Propane
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What is the name of the alkane C4H10?
Butane
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What are the characteristics of alcohol due to?
The functional group -OH
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What is the name of the alcohol CH3OH?
Methanol
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What is the name of the alcohol C2H5OH?
Ethanol
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What can methanol be used for?
A chemical feedstock, in the manufacture of cosmetics
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What can ethanol be used for?
A solvent, a fuel
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Why do alcohols with a shorter structure have a low boiling point?
The intermolecular forces are weak and don't need much energy to overcome them
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Are longer alcohol hydrocarbons more or less soluble in water?
They are less soluble because they behave more like an alkane so they tend to float on top of water due to their low density
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What is produced when alcohols react with sodium?
A salt and hydrogen gas
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What is produced when ethanol and sodium react?
sodium ethoxide and hydrogen
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What happens when sodium is put in alcohol?
The sodium sinks doesn't melt and steadily gives off hydrogen
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What happens when sodium is put in water?
The sodium floats, melts, rushes around on the surface and rapidly gives off hydrogen
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What happens when sodium in mixed with an alkane?
Nothing
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Why do alcohols burn in air?
Because of the presence of a hydrocarbon chain
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How can ethanol be produced?
Sythesis, fermentation, biotechnology
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What is ethanol used for on a industrial scale?
A feedstock, solvent, fuel
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What are the first 3 steps of synthesis to produce ethanol?
1 Crude oil undergoes fractional distillation 2 Long-chain hydrocarbons (alkanes) are vaporised and then cracked using a catalyst and heat 3 Molecules are purified using fractional distillation
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What is the fourth and final step of sythesis to prodcue ethanol?
The ethene that's produced can be used for a feedstock and the remaining water is removed. Ethene is then reacted with steam at a high temperature and pressure in the presence of a catalyst to produce ethanol
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How is ethanonol for use in alcoholic drinks produced?
Fermentation
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What are the three stages of fermentation to produce ethanol?
1. Water and yeast are mixed with natural sugars at just above room temperature 2. Enzymes found in the yeast catalyse the formation of ethanol and carbon dioxide 3. The carbon dioxide can escape from the reaction vessel, but air can't enter it
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What is the word equation for the synthesis of ethanol?
Ethene + Steam -----> Ethanol
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What is the word equation for the fermentation of ethanol?
Glucose -----> Ethanol + Carbon dioxide
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When ethanol solution is manufactured by fermentation, how is the concentration limited?
1. The amount of sugar in the mixture 2. The fact that, above a certain temperature, the ethanol kills the yeast
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How can the concentration of ethanol be increased when the fermentation reaction is over?
Distillation
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What 3 things effect the optimum conditions needed for fermentation?
Temperature, pH, oxygen
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What does the term 'denatured' mean?
The shape is irreversibly changed
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What 2 things are used to produce ethanol using the biotechnology method?
Genetically modified E.coli bacteria, waste biomass
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Why do the E.coli bacteria used in the biotechnology method of producing ethanol have new genes introduced?
So that the bacteria digest all the sugars in the biomass and convert them to alcohol
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What is bioethanol used for?
Fuel
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What are the optimum conditions for the biotechnology process?
1. The temperature should remain 25-37°C 2. The optimum pH levels need to remain constant otherwise the enzyme will be denatured
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The presence of what function group cause the characteristic properties of carboxylic acids?
-COOH
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What is the name of the carboxylic acid HCOOH?
Methanoic acid
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What is the name of the carboxylic acid CH3COOH?
Ethanoic acid
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What type of acid is responsible for the taste of vinegar, the smell of sweaty socks and the taste of rancid butter?
Carboxylic
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Are carboxylic acids more or less reactive than acids like sulfuric acid, nitric acid and hydrochloric acid?
Carboxylic acids are weak therefore are less reactive
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When carboxylic acids react with metals, what is produced?
A salt and hydrogen
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When carboxylic acids react with carbonates, what is produced?
A salt, water and carbon dioxide
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When carboxylic acids are neutralised by alkalis, what is formed?
A salt and water
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What is produced when ethanoic acid and sodium react?
Sodium ethanoate + Hydrogen
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What is produced when ethanoic acid and sodium carbonate react?
Sodium ethanoate + Water + Carbon dioxide
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What is produced when ethanoic acid and sodium hydroxide react?
Sodium ethanoate+ Water
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What forms when carboxylic acids reacts with alcohols?
Esters
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The reaction of carboxylic acids and alcohols which results in the formation of esters is carried out in the presence of what type of catalyst?
Strong acid catalyst
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What have distinct smells which are responsible for the smells and flavours of fruits, are used in the manufacture of perfumes and food products and are also found in solvents and plasticizers?
Esters
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What is the word equation for the reaction of a carboxylic acid and an alcohol?
Carboxylic acid + Alcohol -----> Ester + Water
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What are fats the esters of?
Glycerol, fatty acids
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What are fats and oils?
Naturally occurring esters
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Animal fats are mostly saturated molecules.What type of bonds do they have and are the molecules reactive?
They have single carbon-carbon bonds and they are unreactive
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Vegetable oils are mostly unsaturated molecules. What type of bonds do they have and are the molecules reactive?
They have some double carbon-carbon bonds and they are reactive
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Fill in the gaps. Exothermic changes _______ energy and you can detect this energy because there is usually a temperature change. They release energy because the ______ have less energy that the ______ did.
Release, products, reactants
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Fill in the gaps. Endothermic changes are ____ common than exothermic changes and ______ energy so usually feel cold to touch. You can detect the energy change because the temperature usually ____.
Less, take in, falls
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In a chemical reaction, what must be broken in order to form new products?
The bonds in the reactants
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What is activation energy?
The energy needed to break bonds to start a reaction.
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Is breaking bonds an exo or endothermic process?
Endothermic
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Is making bonds an exo or endothermic process?
Exothermic
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Chemical reactions that absorb more energy to break the bonds in the reactants than is released when new bonds are made in the products are what type of change?
Endothermic
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Chemical reactions in which more energy is released when new bonds are made than was absorbed to break the old bonds are what type of energy change?
Exothermic
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What type of reaction is represented with a double-headed arrow?
Reversible
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Fill in the gaps. In a reversible reaction, the _______ can react together to produce the original _______.
Products, reactants
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If a reversible reaction is in a closed system and is left for long enough, what will it reach?
A state of dynamic equilibrium
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When a dynamic equilibrium is established, why don't the concentration of products (and reactants) change over time?
The forward and backward reactions happen at exactly the same time
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How does the Haber process convert atmospheric nitrogen to ammonia?
By reacting it with hydrogen from natural gas
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What is ammonia used to make?
Fertilisers, explosives, dyes, medicines and a variety of other essential chemicals
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What is a qualitative analysis?
Any method used to identify the chemicals in a substance
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What is a quantitative analysis?
Any method used to determine the amount of chemical in a substance
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What is chromatography used for?
To find out what unknown mixtures are made up of
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Why are substances separated as they move through the stationary phase in chromoatography?
They move at different speeds
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What is the solvent that's used to move the solution in chromatography called?
Mobile phase
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What is the medium that the solvent moves through in chromatography called?
Stationary phase
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What are the first four stages of paper chromatography?
1 Dissolve substance if solid in a solvent 2 Place spot of resulting solution on sheet of chromatography paper on pencil line 3 Place bottom edge of paper in solvent 4 Solvent rises up paper, dissolving spot, carrying it up the paper
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What is the last stage of paper chromatography?
The different chemicals in the mixture separate because their molecules have different sizes and properties
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What are three advantages of thin layer chromatography over paper chromatography?
1. Faster runs 2. More even movement of the mobile phase through the stationary phase 3. A choice of different absorbencies for the stationary phase
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What is the mobile phase in gas chromatography?
A carrier gas
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What is the stationary phase in gas chromatography?
A microscopic layer of liquid on an unreactive solid support
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In gas chromatography, what happens to a sample of a substance when it is injected into one end of the heated column?
It vaporises
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Why is gas chromatography able to separate the components in a mixture?
They have different solubilities
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What are three advantages of using gas chromatography over thin layer chromatography and paper chromatography?
1. Greater separating power 2. Ability to separate complex mixtures 3. Ability to produce quantitative data from very small samples of liquids, gases and volatile solids
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What are two uses of gas chromatography?
1. Detecting banned substances in blood samples 2. Analysing oil spills to identify sources of pollution
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What is retention time?
The time taken for each substance to pass through the chromatographic system
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What are the 6 main stages of a quantitative analysis?
1 Choose analytical method + take sample 2 Measure out sample 3 Dissolve sample if solid 4 Measure property of solution thats proportional to amount of chemical in sample 5 Calculate value from measurements 6 Estimate uncertainty of results
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Card 2

Front

The chemical industry synthesises chemicals on different scales. What chemicals are made on a small scale (fine)?

Back

Drugs, food additives, fragrances

Card 3

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Government have a duty to protect people and the environment. What do they control by imposing strict regulations?

Back

Preview of the front of card 3

Card 4

Front

Following standard procedures, carrying out titrations, scaling up production, interpreting results and carrying out quality assurance are all requirements of what occupation?

Back

Preview of the front of card 4

Card 5

Front

What are the 5 stages of the production of useful chemicals?

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Comments

Faridae

thank you this is really just what I needed :)

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