(a) Methane reacts with chlorine under certain condition to produce tetrachloromethane.
(i) State the condition for the reaction
(ii) Name the type of reaction
(iii) Give two uses of methane
(iv) Name one major natural source of methane
(b)(i) Mention one similarity between the reaction of ethanol with sodium and that of sodium with water
(ii) Write the structure of two isomers of C\(_3\)H\(_8\)O
(iii) Differentiate between a fine chemical and a heavy chemical
(iv) Give one example of each in (b)(iii) above
(c) Two compounds X and Y have the same percentage composition by mass of 92.3% carbon and 7.7% hydrogen. Calculate the:
(i) empirical formula of X and Y;
(ii) molecular formula of each compound if molar mass of X is 26 g and Y is 78g.
(d) A protein is boiled for a long time with dilute HCI and a reaction occurred.
(i) State the type of reaction that occurred
(ii) Name the major product formed
(iii) Give the functional groups present in (d)(ii) above.
Explanation
(a) The condition of the reaction is the presence of ultra-violet light or sunlight.
(ii) Substitution reaction.
(iii) Uses of methane are: (1) It is used as a fuel (2) It is used for making hydrogen, carbon black, carbon (iv) oxide; etc.
(iv) Methane occur as natural gas or refinery gas
(b)(i) (i) Hydrogen is evolved. (ii) Resulting liquid is both colourless (iii) Both reactions are exothermic
(ii)
(iii) Heavy-chemicals are chemicals that pre made in large quantities while fine chemicals are produced in small quantities.
(iv) Examples of heavy chemicals are: H\(_2\)SO\(_4\), NaOH, fertilizer, alum. Examples of fine chemicals are dyes, photographic chemicals, analytical chemicals, drugs.
(c)(i) Empirical formula of X and Y; No of atoms of C = \(\frac{92.3}{12}\) = 7.69
No. of atoms of H = \(\frac{7.7}{1}\)
= 7.7
Ratio of atoms atoms of C:H = \(\frac{7.69}{7.69}\) : \(\frac{7.7}{7.69}\) ; 1 : 1
Empirical formula = CH
(ii) Let the molecular formula of X be (CH)n ; (12 + 1)n = 13n ;
13n = 26
n = \(\frac{26}{13}\) = 2 molecular formula of X =C \(_2\)H \(_2\);
Let the molecular formula of Y be (CH)Y
(12 + 1) Y = 13Y ; 13Y = 78 ; Y = \(\frac{78}{13}\) = 6 ;
Molecular formula of Y = C \(_6\)H \(_6\).
(d)(i) Hydrolysis (ii) Amino acids (iii) Functional groups or amino acids are: amino group (--NH \(_2\)) ai carboxylic group (--COOH).