(a) Write the molecular formula of X. (i) What type of reaction is represented by...
(a) Write the molecular formula of X.
(i) What type of reaction is represented by the equation?
(ii) Consider the following reaction equation: C\(_{12}H_2\) \(\to\) X + C\(_8\)H\(_{18}\)
(iii) Draw the structure of two isomers of X.
(iv) Name the isomers drawn in (a)(iii).
(v) Write a balanced equation for the reaction between X and hydrogen.
(b) Describe one test for fats.
(c) Sulphur (IV) oxide is converted to tetraoxosulphate (VI) acid according to the following equation: 2SO\(_{2(g)}\) + O\(_{2(g)}\) + 2H\(_2\)O\(_{(l)}\) \(\to\) 2H\(_2\)OSO\(_{4(aq)}\). If 1.5 moles of oxgen reacts with sulphur (IV) oxide, calculate the mass of tetraoxosulphate (VI) acid produced. [H = 1.0; O = 16.0; S = 32.0].
(d) Consider the following neutralization reaction:
CH\(_3\)COOH + NaOH \(\to\) CH\(_3\)COONa + H\(_2\)O; \(\bigtriangleup\)H\(_1\)
CH\(_3\)COOH + NH\(_4\)OH \(\to\) CH\(_3\)COONH\(_4\) + H\(_2\)O; \(\bigtriangleup\)H\(_2\)
NaOH + HCl \(\to\) NaCl + H\(_2\)O \(\bigtriangleup\)H\(_3\)
(i) Arrange the enthalphy changes for the reactions in order of increasing magnitude.
(ii) Explain briefly your order in (d)(i).
(e) Consider the following substances. Cu\(_{(s)}\), BeCl\(_2\), NaH\(_{(s)}\), HF\(_{(s)}\)and CCl\(_{4(l)}\). State the substance(s) which;
(i) can conduct electricity;
(ii) is/are soluble in water.
Explanation
(a)(i) Structure of two isomers of X
(ii) Catalytic cracking
(iii) C\(_4\)H\(_8\) (12 - 8) = 4, (26 - 18) = 8
(iv) Name of Isomers drawn in a(iii) are: (A) But - 1- ene (B) But - 2 - ene (C) 2-methyl propene
(v) Balanced equation for the reaction between X and hydrogen.
C\(_4\)H\(_8\) + H\(_2\) ---> C\(_4\)H\(_{10}\)
(b) Test for fats: A small amount of the substance placed on a filter paper then rub or warm or melt on the filter paper. Formation of a translucent spot on the filter paper shows or indicates the presence of fats presence of fat or a small amount of the substance treated with Sudan III reagent/or Add Sudan III to the sample. Observation of a red colour shows the presence of fat.
(c) Molar mass of H\(_2\)SO\(_4\): [(1 x 2) + 32 + (4 x16)]
= 2 + 32 + 64 = 98 — 98g mol\(^{-2}\)
1 mole of O\(_{2(g)}\) --> 2 moles of H\(_2\)SO\(_2\)
1.5 mole of O\(_{2(g)}\) --> (2 x 1.5) moles of H\(_2\)SO\(_4\) 3 moles of H\(_2\)SO\(_4\)
Mass of 3 moles of H\(_2\)SO\(_4\) = 3 x 98 = 294g.
(d) (i) Enthalpy changes for reactions in their increasing magnitude.
\(\bigtriangleup\)H\(_2\) < \(\bigtriangleup\)H\(_1\) < \(\bigtriangleup\)\(_3\) or \(\bigtriangleup\)H\(_2\) \(\bigtriangleup\)H\(_1\) \(\bigtriangleup\)H\(_3\), or \(\bigtriangleup\)H\(_3\) > \(\bigtriangleup\)H\(_1\) > \(\bigtriangleup\)H\(_2\) < lesser than > greater than
(ii) The explanation in the order of arrangement in (d) (i): Neutralization involves the combination of H\(^+\) and OH\(^-\) ions to give a specific amount of energy. The greater the ionization, the greater the energy given off \(\bigtriangleup\)H\(_2\) involves a weak acid and a weak base/weak electrolyte. \(\bigtriangleup\)H\(_1\), involves a stronge base and a weak acid. \(\bigtriangleup\)H\(_3\) involves a strong acid and a strong base.
(e) (i) Cu\(_{(s)}\) can conduct electricity,
(ii) NaH\(_{(g)}\) , BeCl\(_{2(s)}\), HF\(_{(l)}\) are soluble in water.