Aqueous solutions of zinc chloride, calcium chloride iron (lII) tetraoxosulphate (VI) and lead (II) trioxonitrate (IV) are contained in four separate bottles whose labels have been lost. Using aqueous ammonia solution only, show how you would identify the content of each bottle.
Carry out the following exercises on sample C. Record your observations and identify any gases evolved. State the conclusion you draw from the result of each test.
(a) Put about half of sample C into a conical flask and add about 5cm\(^3\) of tetrachloroethane followed by 15cm\(^3\) of water. Shake vigorously for about one minute. Put the resulting mixture into a burette and allow to stand until two layers separate. Run the two layers into two separate conical flasks and label them accordingly.
(b) Using the following reagents only, bench sodium hydroxide solution, aqueous ammonia solution, aqueous lead (II) trioxonite (V) solution, silver trioxonitrate (V) solution. bench trioxonitrate (V) acid. Identify the ions present in the upper layer solution
(c) Add 2 – 3 drops of the lower layer solution to about 2cm\(^3\) of starch solution from your result, name the substances which dissolved in the upper and lower layers.
A solution of a mineral acid containing 0.10 mol of the acid per dm of solution. B IS a solution Containing 1.325g of anhydrous sodium trioxocarbonate (IV) per dm of solution.
(a) Put A into the burette and titrate with 20cm\(^3\) or 25cm\(^3\) portions of B using methyl orange as an indicator. Record the volume of your pipette
(b) From your results and the information is given, calculate;
(i) The number of mole of acid in the average titre
(ii) The number of mole of sodium trioxocarbonate (IV) in the volume of B pipette,
(iii) The mole ratio of acid to base in the reaction [H = 1, C = 12, O = 16, Na 23]
(c) Suggest what the acid in (a) Could be giving reasons for your answer. Hence, write the equation for the reaction.
(a) An element X is represented as \(^{40}_{20} X\)
(i) How many electrons and how many neutrons are present in the atom of X?
(ii) Write the electronic configuration of the atom
(b) Chlorine, whose atomic number is 17, reacts with the element X to form a compound.
(i) What type of bond is formed between X and chlorine?
(ii) Explain how the bond between X and chlorine is formed
(iii) Write the formula of the compound formed and statelhree properties of the compound.
(c) Chlorine has two isotopes of mass numbers 35 and 37 respectively. Suggest the possible relative molar masses of a chlorine molecule.
(d) Calculate the mass of one atom of carbon, given that one mole of carbon weighs 12.0g. (L = 6.02 x 10\(^{23}\))
(a) Write the structural formula of:
(i) 2, 2, 4 – trimethylpentane, (ii) ethylmethanoate, (iii) trans 2, 3 – dimethylbut – 2-ene.
(b) Write the structure of the straight-chain compound that is isomeric with 2,2,4 – trimethylpentane.
(c) Write chemical equations to illustrate the oxidation of: (i) a secondary alkanol (ii) a dihydric alkanol.
(d) When-Crushed cassava was warmed with dilute hydrochloric acid, a sweet-tasting compound, D was obtained. When compcund D was treated with the enzyme, zymase and the mixture distilled a clear and colourleCsliduid, E was obtained. When liquid E was warmed with eth anoic acid i n the presence of a few drops of concentrated tetraoxosulphate (V1) acid, a compound F, with fruity smell was obtained
. (i)To what class of compounds does D belong?
(ii) Name E and F
(iii) Write the fun-ctional group in F
(iv) Write the equation for the reaction between E and ethanoic acid in the presence of concentrated tetraoxosulphate (VI) acid.
(v) Name the type of reaction that takes place between E and ethanoic acid.
(e) Arrange the followingcompounds in their correct order of increasing boiling points: CH\(_3\)CH\(_2\)CH\(_2\)OH, CH\(_3\)CH\(_2\)CH\(_2\)CH\(_2\)CH\(_2\)CH\(_3\) and CH\(_2\)CH\(_2\)CH\(_2\)CH\(_3\); Explain the order.
(a) Explain why transition metals
(i) have high melting points
(ii) have variable oxidation states,
(iii) exhibit paramagnetism
(b) (i) Name the impurities present in bauxite
(ii) State how the impurities in bauxite are removed
(ii) Explain why aluminium oxide is said to be amphoteric.
(c) (i) Describe the electrolysis of copper (II) tetraoxosulphate (VI) solution, using copper electrodes.
(ii) Will the colour of the copper (II) tetraoxosulphate (VI) solution change at the end of the electrolysis described in (c)(i) above? Give reasons for your answer.
(a) Explain with equation where appropriate, the functions of the following substances in the Solvay Process:
(i) limestone,
(ii) ammonia,
(iii) brine.
(b) Explain why the reaction between aqueous sodium trioxocarbonate (IV) solution and dilute hydrochloric acid is a neutralization reaction.
(c) Calculate the mass of sodium trioxocarbonate (IV) produced by the complete decomposition of 16.8g of sodium hydrogen trioxocarbonate (IV) (H = 1, O = 16, Na = 23, S = 33)
State Gay-Lussac’s law and illustrate the law with one chemical reaction.
Distinguish between cracking and reforming. Of what importance are the two processes in the petroleum industry?
(a) Name the major raw materials used in the manufacture of the following:
(i) polythene
(ii) margarine
(iii) cement
(b) State one problem associated with oil producing areas
(a) What is a carbohydrate?
(b) Name two types of carbohydrates and give one example of each type
(a) Write the ionic equation for the reaction between zinc powder and silver trioxonitrate (VI) solution
(b) Which substance in (a) above is (i) oxidized, (ii) reduced?
(c) State two applications of oxidation numbers
(a) How does the collision theory explain the rate of a chemical reaction?
(b) State how each of the following affects the rates of chemical reactions:
(i) surface area (ii) catalyst
50cm\(^{3}\) of sulphur (IV) oxide were produced at s.t.p. when some quantity of powdered sulphur were burnt in excess oxygen
(a) Write the equation for the reaction
(b) Calculate the volume of oxygen used up during the reaction
(c) Which of the gas laws is applicable? State the law.
(a) Arrange the following in their correct order of increasing energy: alpha particles, gamma rays and beta particles
(b) State one difference between nuclear fission and nuclear fusion
(a) Give one example of;
(i) heavy chemicals
(ii) fine chemicals
(b) Write the structural formulae and the names of compounds having the formula CH\(_4\)CI,
(a) Name two allotropes of carbon
(b) Name two products of the destructive distillation of coal and state one use of each.
During the electrolysis of dilute tetraoxosulphate (VI) acid solution 0.05 mole of electrons were passed what volume of gas was produced at the anode? (Gaseous molar volume = 22. 4dm3 at s.t.p)
- A. 0.224 dm3
- B. 0.280 dm3
- C. 0.560 dm3
- D. 2.24 dm3
- E. 22.4 dm3
The reaction represented by the equation C(s) + H2O(l) → CO(s) + H 2(s) was carried out at 27oC if the enthalpy change was + 4500 J and the entropy change was + 12J, what was the free energy change? (∆G = ∆H – T∆S)
- A. - 4176 J
- B. +4176 J
- C. - 900 J
- D. + 900 J
- E. +8100 J
The complex salt formed when aluminium dissolves in sodium hydroxide solution is
- A. Na3AI(OH)4
- B. Na2AI(OH)3
- C. NaAI(OH)3
- D. Na4AI(OH)4
- E. NaAI(OH)4
When copper (ll) chloride solution is treated with excess aqueous ammonia, a deep blue solution results This is due to the presence of
- A. (CuNH4)3+ ions
- B. (CuCI4)2-ions
- C. [Cu(OH)4]2- ions
- D. Cu(H2-O)42+ IONS
- E. [cU(NH3)4] ions