(a) Describe the observation that would be made when—–
i. Sulphur is heated from room temperature till 1190C
ii. 50% trioxonitrate(V) acid acts on copper tunings
(b)i. State two gaseous pollutants that can be generated by burning coal.
ii. What gas is responsible for most of the explosions in coal mines?
iii. The mining of coal leads to environmental pollution. State two environmental effects of the mining activity.
iv. Explain briefly why coal burns more easily when it is in pieces than in lump form
v. Name the non-volitile residue after the destructive distillation of coal
(c)i. Describe a chemical test for water
ii.a. State the effect of boiling a temporary hard water
b. State the effect of adding sodium trioxocarbonate(IV) crystals to permanent hard water
iii. Write an equation for the process of boiling a temporary hard water
(a)i. State two conditions used in the Haber process
ii. Explain briefly the effect of increasing the pressure on the rate of reaction in the Haber process.
(b)i. A mixture of nitrogen(IV) oxide and oxygen is bubbled into warm water to produce
trioxonitrate(V) oxide, write a balanced chemical equation for the reaction.
ii. Using a balanced chemical equation only, explain what would happen if nitrogen(IV) oxide is bubbled into warm water.
iii.
Compare the gases evolved when trioxonitrate(V) acid decomposes under each of the following properties:
i. pH
ii. Solubility in water
iii. Reaction with carbon(II) oxide
(c)i. Name two oxides of sulphur
ii. Write a balanced equation for the reaction between each of the named oxides(Sulphur(IV) oxide, Sulphur (VI) oxide) and water
(d)i. Name one calcium compound
a, Used to dry ammonia gas
b. Used in the manufacture of cement
c. That causes hardness in water
d. Name one calcium compound
(a)i. Define an acid according to the Lewis concept
ii. Give one example of a Lewis acid
(b) Explain salting out in soap preparation
(c) State the reagent and condition necessary for the following conversion
H−C≡C−H→Ag−C≡C−Ag
(d) What is the percentage abundance of an isotope?
(e)i. Why does the element with atomic number 18 not have an oxide?
ii. Explain why chlorine(I) oxide has a low melting point
(f). Describe a test to distinguish between concentrated HNO3 and concentrated H2SO4
(g) State two differences between an electrochemical cell and an electrolytic cell
(h) How does the trend in ionization energy affect the reactivity of group 1 elements?
(i).Define the term molecular formula
(j) State which of the gases H2 and NH3 would deviate more from ideal behaviour. Give reasons for the answer stated above
(a) (i) Define the term Avogadro’s number.
(ii) If 2.30 g of an oxide of nitrogen, x, contains 3.01 x 10\(^{22}\) molecules, calculate the molar mass of x.
(iii) Deduce the formula of x. N, =6.02 x 10″, N =14.0, O = 16.0]
(b)(i) Describe briefly what happens when each of the following substances are added to water:
(I) CCI\(_{4}\); (II) SiCI\(_{4}\),
(ii) Explain briefly why the reactions in (a)(i), (b)(i), (I) and (b)(ii) (II) are different Study the diagram below and answer the questions that follow.
(c) Study the diagram below and answer the questions that follow.
(i) What is the set up used for?
(a)(i) Define the first ionization energy of an element
(ii) Consider the following table and use it to answer te question that follows
| Element | Li | Be | b | C | N | O | F | Ne |
| Atomic number | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 1st I.E/kj mol\(^{-1}\) | 520 | 900 | 801 | 1086 | 1402 | 1314 | 1681 | 2081 |
Explain briefly why the first ionization energy of B is less than that of Be despite the fact that the atomic number of B is greater than that of Be.
(b) When Titanium chloride was electrolysed by passing 0.12 A current through the solution for 500 seconds, 0.015 g of titanium was deposited. What is the charge on the titanium ion?
[ IF= 96500 C, Ti= 48.0 ]
(c)(i) Aluminium can be obtained by the application of electrolysis. State the electrolyte which yields aluminium on electrolysis.
(ii) Name two major factors which would favour the siting of an aluminium smelter in a country.
(d)(i) Define the term paramagnetism.
(ii) Consider the following ions: 24\(^{Cr ^{2+}}\), 24\(^{Cr^{6+}}\)
(I) Deduce the number of unpaired electrons in each of the ions.
(II) State which of the ions will have a greater power of paramagnetism
(l) Give a reason for the answer stated in (d)(ii)(II)
(a)i. With the aid of an equation, explain briefly why aluminum metal is not affected by air.
(ii) In the extraction of aluminum from bauxite, state the:
– substance used for purifying the ore;
– composition of the mixture electrolyzed.
(b) ZnO is an amphoteric oxide. Write equations to illustrate this statement.
(c)i) List three uses of sodium trioxocarbonate(IV).
(ii) Explain briefly why a solution of trioxonitrate(V) acid turns yellowish on storage for some time.
(ii) Describe briefly how trioxonitrate(V) ions could be tested for in the laboratory.
(d) Write balanced chemical equations for the preparation of hydrogen chloride.
(i) using concentrated H\(_{2}\)SO\(_{4}\):
(ii) by direct combination of its constituent elements.
(iii) State one use of hydrogen chloride.
(a) What is the structure of:
(i) graphite:
(ii) diamond
(ii) Explain briefly why diamond is hard and a non-conductor of electricity while graphite is soft and an electrical conductor,
(b)i. State what is achieved at each of the following stages in the purification of town water supply:
– aeration;
– screening
– sedimentation.
(ii) Name two substances responsible for hardness in water.
(iii) State two methods for the removal of hardness in water.
(iv) Give one disadvantage of hard water
(c)i). Describe briefly the extraction of tin from its ore.
(ii) Write a balanced chemical equation for the reaction.
(iii) Write an equation for the reaction of tin with:
– oxygen;
– chlorine.
(a) In an experiment, 25.0 cm\(^{3}\) of H\(_{2}\)SO\(_{4}\) completely neutralized 24.0 cm\(^{3}\) of a 0.1 50 mol dm\(^{-3}\) aqueous KOH using a suitable indicator.
(i) Write a balanced chemical equation for the reaction.
(ii) Calculate the concentration of the acid solution.
(b)i. A burning magnesium ribbon was placed in a gas jar containing Carbon (IV) oxide.
– Write an equation for the reaction.
– Explain briefly why the magnesium ribbon burns in carbon(lV) oxide although the gas does not support combustion.
– Calculate the percentage mass of nitrogen in magnesium trioxonitrate (V). |N = 140. O = 16.0. Mg = 24.01]
(c) Consider the following organic compound: CH\(_{3}\)CH\(_{2}\)CH = CHCOOH.
(i) State two chemical reactions which could he sed te identify the compound.
(ii) What would be observed in each of the reactions stated in c(i)
(d) Describe briefly how soap is manufactured using pellets of sodium hydroxide and vegetable oil
(e) Define the term electronegativity
(a)i. State two characteristics of a homologous series.
(ii) Explain briefly why there are differences in the reaction of ethane and ethene.
(b) When crystals of sodium chloride were warmed with concentrated tetraoxosulphate( VI) acid, a gas was evolved.
(i) Name the gas.
(ii) State two physical properties of the gas.
(iii) Write a balanced chemical equation for the reaction.
(c)i. What are hydrocarbons?
(ii) State two natural sources of hydrocarbons.
(iii) A hydrocarbon contains 83% of carbon by mass. Calculate its empirical formula. [H=1.0, C=12.0]
(d) Draw and label a diagram of a set-up that could be used to electroplate a copper ornament with silver
(a) Distinguish between molecular formula and structural formula
(b) List three factors that determine the ionization energy of an atom.
(c) State the two conditions necessary for the establishment of a chemical equilibrium
(d) Consider the following table
| Element | A | B | C |
| Ionization energy KJ mol\(^{-1}\) | 619 | 518 | 594 |
(d)(i) State which of the elements is the strongest reducing agent.
(ii) Give a reason for the answer stated in (d)(i)
(e) State Graham’s law of diffusion
(f) Consider the following salts: Mg(NO\(_{3}\))\(_{2}\), CaCO\(_{3}\), Na\(_{2}\)SO\(_{4}\). State which of the salts is/are:
(i) readily soluble in water:
(ii) insoluble in water.
(g) Classily each of the following products as addition polymer or condensation polymer:
(i) protein:
(ii) perspex:
(iii) nylon.
(h) Define atomic radius.
(i) Explain briefly why ethanol has a higher boiling point than propane even though they both have comparable molar masses.
(j) State three significance of the pH value in everyday life.
Which of the following scientists discovered the electrons?
- A. Joseph J. Thompson
- B. James Chadwick
- C. Amedeo Avogadro
- D. Ernest Rutherford
A coordinate covalent bond could be formed between?
- A. NH\(_{3}\) and PCl\(_{3}\)
- B. BCl\(_{3}\) and AlCl\(_{3}\)
- C. BCl\(_{3}\) and NH\(_{3}\)
- D. H\(^{+}\) and AlCl\(_{3}\)
Electrovalent compounds normally ————
- A. have low boiling points
- B. have mobile electrons
- C. conduct electricity in the solid state
- D. dissolve in polar solvent
Which of the following statements about elements in Group VII is correct?
- A. Br\(_{2}\) will oxidize CI\(^{-}\)
- B. F\(_{2}\) has the least tendency to be reduced
- C. Cl\(_{2}\) will oxidize I\(^{-}\)
- D. l\(_{2}\) is a stronger oxidizing agent than F\(_{2}\)
Which of the following pairs of molecules form hydrogen bonds?
- A. C\(_{2}\)H\(_{5}\)OH and CH\(_{3}\)OH
- B. CH\(_{3}\)OH and H\(_{2}\)
- C. H\(_{2}\)S and CH\(_{4}\)
- D. NH\(_{3}\) and SO\(_{2}\)
The isotopes of neon are represented by the symbols \(^{20}\)\(_{x}\) Ne, \(^{21}\) \(_{y}\) Ne, and \(^{22}\) \(_{z}\) Ne. The relationship between x, y, and z is?
- A. x > y > z
- B. x < y < z
- C. x = y= z
- D. x < z < y
How many molecules of oxygen would occupy a volume of 2.24 cm\(^{3}\) at s.t.p?
[Molar volume at s.t.p = 22,400 cm\(^{3}\), Avogadro’s number = 6.02 x 10\(^{23}\)]
- A. 3.01 x 10\(^{20}\)
- B. 3.01 x 10\(^{27}\)
- C. 6.02 x 10\(^{19}\)
- D. 6.02 x 10\(^{27}\)
Consider the following energy profile diagram and use it to answer the question that follows
The energy profile diagram illustrates————-
- A. an endothermic reaction
- B. an exothermic reaction
- C. a spontaneous reaction
- D. a redox reaction
Consider the following energy profile diagram and use it to answer the question that follows
The enthalpy change of the reaction is————
- A. E\(_{A}\)
- B. E\(_{B}\)
- C. E\(_{C}\)
- D. E\(_{D}\)
Consider the following energy profile diagram and use it to answer the question that follows
The activation energy of the reaction is
- A. E\(_{A}\)
- B. E\(_{B}\)
- C. E\(_{C}\)
- D. E\(_{D}\)
Protons and electrons are called fundamental particles because they———-
- A. are indivisible
- B. have different charges
- C. are the lightest particles
- D. are found in all matter