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28 Cards in this Set
- Front
- Back
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What is fractional distillation? |
A separation technique of crude oil (a mixture of mainly hydrocarbons). As the boiling points of compounds depends on their mass, all the different hydrocarbons in crude oil have different boiling points. |
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What are the principles of fractional distillation? |
The crude oil is heated before it is addd to the fractionating column. The compounds boil and form a vapour that rises up the tower. The temperature decreases as you go higher up you go, so the vapour condenses and leaves the fractionating column. |
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Which compounds are produced in order of lowest boiling points to highest boiling points? (during fractional distillation) |
Refinery gases Gasoline Kerosene Diesel Fuel oil Bitumen |
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What are the uses and viscosity of refinery gases? |
camping fuels, gases |
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What are the uses and viscosity of gasoline? |
Fuel in cars, very runny |
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What are the uses and viscosity of kerosene? |
Oil stoves and aircraft fuel, quite runny |
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What are the uses and viscosity of diesel? |
Fuel in diesel engines, runny |
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What are the uses and viscosity of fuel oil? |
Lubricants and making waxes and polishes, quite thick |
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What are the uses and viscosity of bitumen? |
Making roads, high viscosity slow to pour. |
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When fuels are burnt in oxygen, what are the products? |
Carbon dioxide and water? |
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What happens when incomplete combustion occurs when burning fuels? |
Carbon monoxide (a poisonous gas) is produced. |
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What happens when sulphur oxides and nitrogen oxides dissolve are released into the atmosphere? |
They contribute to acid rain which erodes buildings made of limestone and reacts with the metals in the buildings. It also makes rivers acidic (harmful to wildlife) and damages vegetation. |
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What characteristics do the compounds in the homologous series share? |
The same functional group and therefore the same general formula. All compounds do the same chemical reactions, a gradual change in physical properties e.g. boiling points, colour and viscosity. Neighbouring members differ by a CH2 group. |
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What are carboxylic acids? |
The carboxylic acids are a homologous series of organic compounds.Carboxylic acids contain the carboxyl functional group (-COOH). Carboxylic acids end in '-oic acid'.The carboxyl group will never have a position number in a carboxylic acid, as it is always on the end of the carbon chain.The basic rules of naming apply. Carboxylic acids take their names from their ‘parent’ alkanes. For example, ethane is the ‘parent’ alkane of ethanoic acid |
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Structure of carboxylic acids? |
Ethanoic acid has the formula CH3COOH and this structure: |
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Properties of carbyoxylic acids? |
Short carboxylic acids are liquids and are soluble in water. Longer carboxylic acids are solids and are less soluble in water.The boiling point of a carboxylic acid is higher than that of the alkane with the same number of carbon atoms because the intermolecular forces are much stronger.Carboxylic acids are weak acids, so they can donate a hydrogen ion (H+) in acid-base reactionThis means that they will react with carbonates to produce a salt, water and carbon dioxide. They will also react with reactive metals to produce a salt and hydrogen. |
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How do you make carbyoxylic acid? |
Ethanoic acid can be made by oxidising ethanol (which is an alcohol). In this case, oxidation involves adding an oxygen atom and removing two hydrogen atoms. This can happen:during fermentation if air is presentwhen ethanol is oxidised by an oxidising agent, such as acidified potassium manganate(VII) |
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What is an Ester? |
Esters occur naturally - often as fats and oils - but they can be made in the laboratory by reacting an alcohol with an organic acid. A little sulfuric acid is needed as a catalyst.The general word equation for the reaction is:alcohol + organic acid → ester + waterFor example:methanol + butanoic acid → methyl butanoate + water |
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Describe the strucutre of an ester reaction. |
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Which alcochol and organic acid creates the following esters and what do they smell like? Pentyl Ethanoate Octyl Ethanoate Pentyl Butanoate Methyl Butanoate |
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How is oil (vegetable - natural occuring ester) extracted? |
Vegetable oils are natural oils found in seeds, nuts and some fruit. The oil can be extracted. The plant material is crushed and pressed and the oil, eg olive oil, is squeezed out.Sometimes the oil is more difficult to extract and has to be dissolved in a solvent. Once the oil is dissolved, the solvent is removed by distillation and impurities (such as water) are also removed. This leaves pure vegetable oil, eg sunflower oil. |
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How are vegetable oils used in cooking? |
Vegetable oils have higher boiling points than water - so foods can be cooked or fried in vegetable oils at higher temperatures than they can be if they are cooked or boiled in water.Food cooked in vegetable oils:cook faster than if they were boiledhave different flavours than if they were boiledVegetable oils are a source of energy in the diet. Food cooked in vegetable oils releases more energy when it is eaten than food cooked in water. This can have an impact on our health and cause excess weight.Some vegetable oils can be converted to biodiesel by reacting them with methanol. This allows certain crops to be grown and used to make fuels for cars and lorries without needing to use fossil fuels. This can help to make biodiesel carbon neutral. |
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What are saturated fats and oils? |
The fatty acids in some vegetable oils are saturated - they only have single bonds between their carbon atoms. Saturated oils tend to be solid at room temperature, and are sometimes called vegetable fats instead of vegetable oils. Lard is an example of a saturated oil. |
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What are unsatuated fats and oils? |
The fatty acids in some vegetable oils are unsaturated - they have double bonds between some of their carbon atoms. Unsaturated oils tend to be liquid at room temperature, and are useful for frying food. They can be divided into two categories: monounsaturated fats have one double bond in each fatty acid polyunsaturated fats have many double bonds Unsaturated fats (rather than saturated fats) are thought to be a healthier option in the diet. |
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What is an emulsion? |
Vegetable oils do not dissolve in water. If oil and water are shaken together, tiny droplets of one liquid spread through the other liquid, forming a mixture called an emulsion.Emulsions are thicker than the oil or water they contain. This makes them useful in foods such as salad dressings and ice cream. Emulsions are also used in cosmetics and paints.There are two main types of emulsion: oil droplets in water (milk, ice cream, salad cream, mayonnaise) water droplets in oil (margarine, butter, skin cream, moisturising lotion) |
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What are emulsifiers? |
If an emulsion is left to stand, eventually a layer of oil will form on the surface of the water. Emulsifiers are substances that stabilise emulsions, stopping them separating out. Egg yolk contains a natural emulsifier. Mayonnaise is a stable emulsion of vegetable oil and vinegar with egg yolk. |
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What are the two different ends of emulsifier molecules? |
a hydrophilic (water-loving) ‘head’ that forms chemical bonds with water but not with oils a hydrophobic (water-hating) ‘tail’ that forms chemical bonds with oils but not with water |
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What is the hydrogenation of saturated vegetable fats? |
Saturated vegetable fats are solid at room temperature, and have a higher melting point than unsaturated oils. This makes them suitable for making margarine or for commercial use in the making of cakes and pastry. Unsaturated vegetable oils can be ‘hardened’ by reacting them with hydrogen, a reaction called hydrogenation. During hydrogenation, vegetable oils are reacted with hydrogen gas at about 60°C. A nickel catalyst is used to speed up the reaction. The double bonds are converted to single bonds in the reaction. In this way, unsaturated fats can be made into saturated fats – they are hardened. |
