1) Fats and oils squeeze out be described as esters of glycerol, C3H8O3.
(a)(i)Draw the coordinate of glycerol.
(i)CH2OHCHOHCH2OH;1
(ii)Glycerol can react with three molecules of stearic acid, C17H35COOH, to put to work a triglyceride. Deduce the number of carbon atoms in iodine molecule of this triglyceride.
57(1)
(iii)A triglyceride is also formed in the reaction between glycerol and three molecules of oleic acid, C17H33COOH. State and justify which of the two triglycerides
(the one formed from stearic acid or the one formed from oleic acid) has the higher melting point.
(the one from) stearic acid;
saturated / no (C to C) double bonds;
chains cantonment close together / stronger intermolecular forces / van der Waals
forces etc;3
Ignore total heat bonding. If wrong choice made, further third mark can be scored. (3)
(b)An oil sample containing 0.0100 mol of oil was erect to react with 7.61 g of iodine, I2.
Determine the number of C=C double bonds present in each molecule of the oil.
(b)[pic]= 0.
03 (mol)
3 (double bonds) (extracellular fluid);2
Correct answer scores [2]. If 6 is given, with no working, cede [1].
(2)
[May 2006 SL P3]
ER: In (a), the structure of glycerol was well cognize by the better candidates, although quite a number of alcohols with only one OH group, or with to a greater extent than one OH group on the same carbon, were seen. A wide variety of answers to (a)(ii)was seen, predictably including 54. at that place were many a(prenominal) errors seen in the stearic acid question, the most practiced being the suggestion that CC (or C=C) bonds were more easily broken. In part (b), there were inevitably many candidates who used the coition atomic mass instead of the relative molecular mass of iodine in the calculation (for which ECF was allowed), and a surprising number failed to go on to verbalize the...If you want to get a full essay, order it on our website: Orderessay
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