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Flow Chart Showing Tests to Identify All 8 Chemicals

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Flow Chart Showing Tests to Identify All 8 Chemicals Background Information & Methods for Testing: Alkenes5&6: Alkenes are hydrocarbons which are formed by cracking larger hydrocarbons. Unlike alkanes, alkenes are unsaturated due to the double bond between the carbon atoms. They have the general formula CnH2n. An example of an alkene is ethene. It has the structural formula C2H4. Molecular Formula: C2H4 = CH2=CH2 Structural Formula of Ethene: Double bond between Carbon atoms Hydrogen atoms To test for an alkene, I will mix the unknown organic compound with bromine water. The solution will turn from orange to colourless in the presence of an alkene. This will prove that a double bond is present; therefore the liquid was an alkene. The double bond between the carbon atoms will open up and bromine will be added on forming a haloalkane, for example Bromoethane. Add 5cm3 of the unknown liquid into a boiling tube. Then add 2cm3 of Bromine water to the liquid and mix well. If the solution decolourises, it will indicate that the unknown liquid was an alkene.6 Equation for the reaction: Phenols4: Phenols are made of a benzene ring attached to a hydroxyl group. ...read more.


Molecular Formula of Propanal: CH3CH2CHO Structural Formula of Propanal: Double bond between Carbon and Oxygen Carbon Alkyl Group Hydrogen atoms To test for aldehydes, add 0.5cm3 of the unknown solution to a test tube and add 2cm3 of the 2, 4 DNPH solution and shake. Then add 10 drops of Tollen's reagent to the solution. A silver mirror should form on the surface of the test tube within 3-5 minutes.1 Equation for the reaction: Carboxylic Acids: Carboxylic acids are weak acids, hence only small amounts of its molecules dissociate in water. Carboxylic acids are however, stronger than alcohols due to the weakening of the O-H bond in the acid because of the presence of the carbonyl group and also because of the stability of the anion formed when the H+ ion leaves. Ethanoic Acid is an example of a Carboxylic Acid. It consists of an OH group, an alkyl group and a double bond between Carbon2 and oxygen. Molecular Formula of Ethanoic Acid: CH3COOH = CH3C=OOH Structural Formula of Ethanoic Acid: Carbon2 Double bond between Carbon2 and Oxygen OH Group Alkyl Group To test for Carboxylic acid, I will react the liquid with some sodium hydrogen carbonate. ...read more.


The solution that will decolourise will show that the original solution used was a tertiary alcohol. (3) Equation for the reaction: Safety: Source of hazard Hazard Precautions taken Acidified potassium dichromate (vi) Toxic if inhaled, swallowed or absorbed by skin; corrosive; can cause severe eye damage. Reacts vigorously with reducing agents and may explode. Conduct tests in a fume cupboard. Do not inhale or swallow. Use hand and eye protection. Keep away from reducing agents and other chemicals. Mixing chemicals Chemical may splash into eyes Wear safety goggles Acids Spillage/ contact with body Wear gloves and lab coat Phenol Irritant when in contact with skin Wear goggles, gloves and lab coat. In case of contact with skin, wash under warm water. Bromine vapour Toxic; could cause severe burns to eyes and skin. Use hand and eye protection. In case of contact with skin, seek medical advice Alkenes Highly flammable Keep away from naked fires/ flames Tollen's reagent Can be irritant if in contact with eyes and skin Wear hand/ eye protection. If in contact with skin or eyes, wash with plenty of water. Sodium carbonate Slightly toxic. May cause irritation of the and blistering if in excessive contact. May be corrosive to eyes. Wear hand/ eye protection at all times. Avoid inhalation. Wash thoroughly if in contact with skin or eyes and seek medical advice. ...read more.

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