(a)(i) Define the term functional group. (ii) Name the functional groups present in the following compound: (b) Consider the following structure of an organ...
(ii) Name the functional groups present in the following compound:
(b) Consider the following structure of an organic compound, Q.
(1) Name compound Q.
(ii) Write the balanced equation for the complete combustion of compound Q.
(iii) What type of reaction will compound Q undergo with chlorine?
(vi) Draw the structure of-the alkene that is an isomer of compound Q.
(c) A chemistry student was provided with four samples of organic compounds, A, B, C, and D. Samples A and B each decolourized bromine in tetrachloromethane but only sample B reacted with a solution of ammoniacal silver trioxonitrate (V) to give a white precipitate. Sample D reacted with sodium trioxocarbonate (IV) to liberate carbon (IV) oxide. When heat was applied to the mixture of samples C and D in a test tube and drops of concentrated tetraoxosulphate (VI) acid added, a product with a fruity odour was formed.
(i) Name the family of organic compounds to which samples A, B, C, and D belong.
(ii) State why samples A and B reacted with bromine in tetrachloromethane.
(iii) State the reason why sample B gave a white precipitate with the solution of ammoniacal silver trioxocarbonate (V).
(iv) Give the name o f the reactions between' samples C and D.
(v) State the two roles of the concentrated tetraoxosulphate (VI) acid in the reaction in (a)(iv).
(d) (i) Describe briefly the production of biogas using a biogas generator.
(ii) State two uses of biogas.
(a)(i) A functional group is an atom, a bond, or a group of atoms in an organic compound which determines its characteristic chemical properties.
(a)(ii) The functional groups present are:
hydroxyl (alkanol) group, −OH;
alkanoate (ester) group, −COO−.
(b)(i) Compound Q is cyclopropane.
(b)(ii) The balanced equation for its complete combustion is:
\[2C_3H_6 + 9O_2 \rightarrow 6CO_2 + 6H_2O\]
(b)(iii) Cyclopropane undergoes a substitution reaction with chlorine.
(b)(iv) The alkene isomer of cyclopropane is propene, with structural formula:
Displayed structural formula of propene, the alkene isomer of cyclopropane.
(c)(i)
Sample
Family of organic compound
A
Alkene
B
Alkyne
C
Alkanol
D
Alkanoic acid
(c)(ii) Samples A and B decolourize bromine in tetrachloromethane because they are unsaturated compounds. They contain carbon-to-carbon multiple bonds which add bromine.
(c)(iii) Sample B is a terminal alkyne. Its terminal hydrogen is replaced by silver ions in ammoniacal silver trioxonitrate(V) solution to form an insoluble white silver alkynide precipitate.
(c)(iv) The reaction between C and D is esterification.
a dehydrating agent, removing water formed and favouring ester formation.
(d)(i) Organic waste such as animal dung and plant materials is mixed with water and fed into an airtight biodigester. In the absence of air, anaerobic bacteria decompose the waste and produce biogas, mainly methane with carbon(IV) oxide. The gas collects in the dome of the digester and is taken out through a gas outlet. The residual slurry can be used as manure.
(a)(i) A functional group is an atom, a bond, or a group of atoms in an organic compound which determines its characteristic chemical properties.
(a)(ii) The functional groups present are:
hydroxyl (alkanol) group, −OH;
alkanoate (ester) group, −COO−.
(b)(i) Compound Q is cyclopropane.
(b)(ii) The balanced equation for its complete combustion is:
\[2C_3H_6 + 9O_2 \rightarrow 6CO_2 + 6H_2O\]
(b)(iii) Cyclopropane undergoes a substitution reaction with chlorine.
(b)(iv) The alkene isomer of cyclopropane is propene, with structural formula:
Displayed structural formula of propene, the alkene isomer of cyclopropane.
(c)(i)
Sample
Family of organic compound
A
Alkene
B
Alkyne
C
Alkanol
D
Alkanoic acid
(c)(ii) Samples A and B decolourize bromine in tetrachloromethane because they are unsaturated compounds. They contain carbon-to-carbon multiple bonds which add bromine.
(c)(iii) Sample B is a terminal alkyne. Its terminal hydrogen is replaced by silver ions in ammoniacal silver trioxonitrate(V) solution to form an insoluble white silver alkynide precipitate.
(c)(iv) The reaction between C and D is esterification.
a dehydrating agent, removing water formed and favouring ester formation.
(d)(i) Organic waste such as animal dung and plant materials is mixed with water and fed into an airtight biodigester. In the absence of air, anaerobic bacteria decompose the waste and produce biogas, mainly methane with carbon(IV) oxide. The gas collects in the dome of the digester and is taken out through a gas outlet. The residual slurry can be used as manure.
