PAHANG TRIAL 2009 EXAMINATION CHEMISTRY PAPER 2 MARKING SCHEMES SECTION A - Structural Questions: Question 1. (a) (i) The presence of isotopes 1M (ii) Let the abundance of 63X be a %. The % abundance of 65X. = ( 100 – a ) 1M Relative atomic mass = ( 62.93 x a) + ( 64.93 x ( 100 -a) ) 1M
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was 19.1 ppm. This signal was first to most upfield and shielded in the spectrum because of the high electron density of carbon. This signal was agreed to a literature value for a CH3 group between 5-30 ppm. Signal 2 was branched to signal 1‚ and had the same value‚ but it was agreed for the literature range for a CH2 group. Signal 3 had an observed peak value of 21.134 ppm and a calculated peak value of 20.8 ppm. This peak was agreed for the literature value range between 13.35 ppm. Signal 4 had
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Experiment C. Aim: To protect one of two carbonyl groups (C1) in order to allow the other to react twice with a Grignard followed by removal of the protecting group by acid hydrolysis to give final product (C2). Method: Ethyl acetoacetate (30.03g)‚ ethylene glycol (15.01g) and toluene-p-sulphonic acid (0.13g) were added to a 250 cm3 round bottomed flask‚ containing a stirrer bar and toluene (100 cm3)‚ fitted with a condenser and dean-stark head. Solution was heated strongly under reflux using
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substituent and the benzene ring taken together constitute a new parent name. Four important examples are: CH3 OH NH2 COOH F F F Fluorobenzene * Because all H atoms in benzene are equivalent it doesn’t matter at which vertex of the ring the substituted group is located. F Toluene Phenol Aniline Benzoic Acid (not methyl benzene‚ hydroxybezene‚ aminobenzene‚ carboxyl benzene) Examples: CH3 HO Cl 2- Chlorotoluene F 3- Fluorophenol Note 2: For monosubstituted benzene rings that have a group attached
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For example alcohols react with acid anhydrides to form esters: O CH3CH2OH Ethanol + O H3C O O CH2CH3 + CH3COOH Acetic acid C C H3C CH3 O Acetic anhydride Ethyl acetate Acid chlorides form esters by reaction with alcohols. O CH3CH2CH2OH 1-Propanol + H3C Cl Acetyl chloride C H3C O C O CH2CH2CH3 + HCl n-Propyl acetate In the latter reaction‚ an organic base such as pyridine
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in nature.’ What does this statement mean? Express the relation between conductivity and molar conductivity of a solution held in a cell. Define ’electrophoresis’. Draw the structure of XeF2 molecule. Write the IUPAC name of the following compound: (CH3)3 CCH2Br 6. 7. Draw the structure of 3-methylbutanal. Arrange the following compounds in an increasing order of their solubility in water: C6H5NH2‚ (C2H5)2NH‚ C2H5NH2 182 3. 4. 5. 8. 9. What are biodegradable polymers? The chemistry of corrosion
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reaction | Did not mix | 2-Propanol | No reaction | Mixed and the color turned red | 2-Methyl-2-Propanol | Change in color (yellow) | Bubbles and turned pink | Discussion: Butanol: H3C-CH2-CH2-CH2-OH 2-Propanol: H3C-CHOH-CH3 2-Methyl-2-Propanol: 2-Methyl-2-Propanol is only alcohol reacted with HCL 2-Methyl-2-Propanol+HCL=====>2-chloro-2-methylpropane+ H2O substitution reaction 2-Propanol+KMnO4=====>Propan-2-one
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straight down. Step 3 Next‚ add the two remaining bonds at each carbon‚ arranged as shown to give the correct bond angles. Step 4 Finally‚ add the symbols for the elements. Exercise Draw a sawhorse projection of 1‚2-ethanediol‚ HO-CH2-CH2-OH in both staggered and eclipsed conformations. staggered conformation eclipsed conformation Newman Projection End-on representations for conformations are commonly drawn using a convention called a Newman projection. A Newman projection
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ABSTRACT At First my heartiest air towards to ALLAH‚ then thanks to our course teacher Mr.Rajib saha who give me chance to work regarding Detergent. A detergent is an agent used for cleaning. Detergents are synthetic surfactants‚ which is produced from petrochemicals rather than fatty acids and oils. They are very effective in hard‚ soft as well as salt water. Detergents are the salts of long chain of hydrocarbons such as alkyl sulphates. A detergent has several advantages over soaps in which we
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Taking the 3H integrated signal together with the 2H quadruplet signal‚ this combined integration and splitting pattern was indicative of a CH2-CH3 group being present on the unknown molecule. The three hydrogens on the end of the molecule have only 2 neighboring hydrogens; according to the n+1 rule‚ the 3H integrated hydrogens therefore appear as a triplet splitting pattern. The 2H integrated
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