Chemical reactions for UNIT 2 OCR AS chemistry 0.0 / 5 ? ChemistryReactionsASOCR Created by: carys ☺Created on: 28-04-13 18:35 What are the conditions needed for alkanes to reaction with halogens? UV radiation or temperatures of 300 degrees. 1 of 17 What is propagation? The two repeated steps in radical subsitution that build up the products in a chain reaction. 2 of 17 What is termination? the step at the end of radical subsitution when two radicals combine to form a molecule. 3 of 17 What are the conditions needed for ethene to become ethane? A mixture of hydrogen gas and a gaseous alkene is passed over a catalyst of nickel at a temperature of 150 degrees. 4 of 17 What does the bromine test show? If the colour changes from orange to colourless, there is a double bond. If there is no colour change, there are no double bonds. 5 of 17 What are the conditions needed for the addition of hydrogen halides? hydrogen halides in gas state (at room temperature) and are bubbled into liquid alkanes. 6 of 17 What are the conditions needed for the addition of steam? steam and gaseous alkene are heated to a high temperature and pressure and a H3PO4 (phosphoric acid) catalyst used 7 of 17 What are the conditions needed for radical polymerisation? temperatures of 200 degrees, and very high pressures. 8 of 17 What are the conditions needed for the ziegler-natta process? TiCl3 and Al(C2H5)2Cl catalysts at 60 degrees. 9 of 17 What are the conditions needed for the fermentation (of glucose into ethanol) yeast (zymase enzyme) at 37 degrees 10 of 17 How do primary alcohols become aldehydes? Gentle heating with acidified potassium dichromate (K2Cr2O7/H2SO4) and distilled immediately. 11 of 17 How do primary alcohols become carboxylic acid? Stronger heating under reflux with excess K2Cr2O7/H2SO4 12 of 17 How do primary alcohols become ketones? heating using K2Cr2O7/H2SO4 13 of 17 What is the colour change of potassium dichromate during oxidation of alcohols? orange to green 14 of 17 How are esters formed? Esterification; an alcohol is warmed with a carboxylic acid in the presence of an acid catalyst (e.g. H2SO4 at 80 degrees) 15 of 17 What are the conditions for the dehydration of an alcohol? Concentrated phosphoric acid (H3PO4) or concentrated sulfuric acid (H2SO4) heated under reflux for 40mins. 16 of 17 What are the conditions for the hydrolysis of halogenoalkanes? heated uder reflux with an aqueous sodium hydroxide 17 of 17
Comments
No comments have yet been made