Heep Woh College

Form 5 Chemistry Quiz 9

Chapter 26 : Alcohols

Marking Schemes

 

1.    (a)        Photosynthesis                          (correct spelling)                                                     1

 

        (b)  (i)        Act as catalyst / speed up reaction / increase the rate of reaction        1

 

                       (ii)        C₁₂H₂₂O₁₁ + H₂O ¾® 2C₆H₁₂O₆                                                                           1

C₆H₁₂O₆ ¾® 2CH₃CH₂OH + 2CO₂ 1

 

        (c)        Different boiling point.                                                                                               1

 

        (d)        Refer to NOTE: C26/6                                                                                              3

                       Close system – 0 marks

                       Water in / out – 1 mark

                       Thermometer – 1 mark

                       Correct set up (with fractionating colume) – 1 mark                   

 

2.    (a)  (i)        Water / Steam +                                                                                                   1

concentrated sulphuric acid / concentrated phosphoric acid 1

       

                (ii)        CH₂=CH₂ + H₂O ¾® CH₃CH₂OH                                                              1

 

(b)  (i)        acidified potassium dichromate / permanganate                                      1

       reflux / heat / warm                                                                                            1

 

(ii)        Refer to NOTE: C26/11 or C26/16                                                                 2

                               Close system – 0 marks

                               Water in / out / vertical condenser / cold finger – 1 mark

                               Correct set up – 1 mark                   

                      

(iii)        CH₃CH₂OH + 2[O] ¾® CH₃COOH + H₂O                                                        1

 

        (c)  (i)        2CH₃COOH + 2Na ¾® 2CH₃COO^-Na⁺ + H₂                                                 1

                      

(ii)        Neutralization. Salt / sodium ethanoate is formed.                                 1

 

        (d)  Both ethene and ethanol are simple molecules.                                         1

                       Intermolecular force / hydrogen bond of ethanol is higher than ethene.                                                                                                                                                               1

 

 

The End