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Questions and Answers
What is the purpose of bubbling the ethyne produced through acidified copper sulphate?
What is the purpose of bubbling the ethyne produced through acidified copper sulphate?
What is the characteristic of the carbon bonds in a benzene ring?
What is the characteristic of the carbon bonds in a benzene ring?
What is the physical state of aromatic compounds with low Mr?
What is the physical state of aromatic compounds with low Mr?
What is the solubility of aromatic compounds in water?
What is the solubility of aromatic compounds in water?
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What is a major safety concern when working with calcium dicarbide?
What is a major safety concern when working with calcium dicarbide?
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What is the purpose of adding a purple dye to methanol when it is used as a fuel?
What is the purpose of adding a purple dye to methanol when it is used as a fuel?
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What type of bonds are involved in planar organic compounds?
What type of bonds are involved in planar organic compounds?
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What is the equation for the fermentation of sugars in fruits and vegetables?
What is the equation for the fermentation of sugars in fruits and vegetables?
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What is the main reason why ethanol is a liquid at room temperature, while propane is a gas?
What is the main reason why ethanol is a liquid at room temperature, while propane is a gas?
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What is the primary difference between a primary and secondary alcohol?
What is the primary difference between a primary and secondary alcohol?
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What is a common use of ethanol as a polar solvent?
What is a common use of ethanol as a polar solvent?
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What is the main difference between methanol and ethanol?
What is the main difference between methanol and ethanol?
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What is the purpose of chloroalkanes in dry-cleaning?
What is the purpose of chloroalkanes in dry-cleaning?
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Why are chloroalkanes classified as non-polar?
Why are chloroalkanes classified as non-polar?
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What is the trend in the solubility of alcohols as the chain length increases?
What is the trend in the solubility of alcohols as the chain length increases?
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Study Notes
Preparation of Ethyne Experiment
- Calcium dicarbide is a grey solid that cannot be obtained in a pure state.
- Ethyne is obtained from calcium dicarbide and is usually contaminated with gases like hydrogen sulphide and ammonia.
- These impurities are removed by bubbling the ethyne produced through acidified copper sulphate.
- Calcium dicarbide is extremely flammable and should be used in small amounts to avoid explosion risks.
Aromatic Compounds
- Aromatic compounds have a benzene ring in their structure, which contains six carbons in a ring.
- The carbon bonds in the benzene ring are intermediate between C-C and C=C due to delocalised pi bonding.
- Aromatic compounds are classified as unsaturated.
- They are non-polar, insoluble in water, and are good non-polar solvents.
Properties of Aromatic Compounds
- Physical State: low Mr → liquids at room temp, high Mr → solids at room temp
- Solubility: non-polar, insoluble in water, good non-polar solvents
- Must-known structures: benzene, methylbenzene, ethylbenzene
- Benzene is carcinogenic, while some of its derivatives are not (e.g., aspirin, phenolphthalein).
Fuels and Other Compounds
Chloroalkanes
- Chloroalkanes are alkanes where at least one hydrogen atom has been replaced by a chlorine atom.
- They are saturated compounds, usually liquids, and rarely found in nature.
- Although the C-Cl bond is polar, it is not polar enough to allow chloroalkanes to dissolve in water.
- They are classified as non-polar because they are soluble in cyclohexane.
- Uses of chloroalkanes include anaesthetics (chloroform) and solvents.
Alcohols
- All alcohols contain a hydroxyl (OH) group, and their names end in "ol".
- There are three types of alcohols: primary, secondary, and tertiary.
- Primary alcohols undergo oxidation reactions to form aldehydes, while secondary alcohols undergo oxidation reactions to form ketones.
- Physical State & Properties of Alcohols: similar physical properties (same physical state, same boiling point) when comparing propane and ethanol.
Intermolecular Forces
- Hydrogen bonding occurs in alcohols because hydrogen is bonded to oxygen, resulting in a strongly polar OH bond.
- Ethanol is soluble in water because H₂O is a polar solvent, and ethanol and water are completely miscible due to the formation of hydrogen bonds.
Production of Ethanol
- Ethanol can be produced through hydration of ethene or fermentation of sugars in fruits and vegetables.
- Fermentation is an anaerobic process during which enzymes found in yeast break down sugars into alcohol.
- Ethanol has various everyday uses, including as a polar solvent in paints, aftershaves, and perfumes, and as a fuel.
Methanol
- Methanol is a poisonous alcohol and usually contains a purple dye when added to fuels such as methylated spirits to prevent consumption by people.
- Methanol used in this way is said to be a denaturing agent.
Planar and Tetrahedral Organic Compounds
- These compounds have atoms on the same plane (i.e., all atoms are "flat") and involve double or triple bonds.
- Examples include ethene, alkenes, alkynes, aldehydes, ketones, carboxylic acids, esters, and aromatic compounds.
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Description
This quiz is about the preparation of ethyne experiment, including the use of calcium dicarbide, removing contaminants, and safety precautions.
