SS 2 Chemistry Third Term Examination
THIRD TERM
Examination Malpractices May Lead to a Repeat of the Subject or Suspensions. Don’t Be Involved.
SUBJECT: CHEMISTRY
CLASS: S.S.S TWO
DURATION: 2 HR
OBJECTIVE QUESTIONS
- Water is temporarily hard because it contains
- a. CaSO₄
- b. MgSO₄
- c. Chlorine
- d. Ca(HCO₃)₂
- The following are characteristics of colloids except
- a. Tyndall effect on light beam
- b. Solid phase is removed by dialysis
- c. Colloidal particles are larger than that of suspensions
- d. Colloidal particles are separated using parchment membranes
- One of these is not a water pollutant
- a. Petroleum
- b. Domestic liquid and solid waste
- c. Industrial effluents
- d. Biodegradable chemicals
- 144 g of KCl dissolved in 1 dm³ of water at 90°C in the presence of excess crystals of KCl. Calculate the solubility of KCl at this temperature. (K = 39, Cl = 35.5)
- a. 0.89 mol dm⁻³
- b. 1.93 mol dm⁻³
- c. 1.75 mol dm⁻³
- d. 1.5 mol dm⁻³
- What is the volume occupied by 2 moles of ammonia at S.T.P?
- a. 44.8 dm³
- b. 22.4 dm³
- c. 11.2 dm³
- d. 5.6 dm³
- Consider the neutralization reaction represented by the following equation: Na₂CO₃ + 2HNO₃ → 2NaNO₃ + H₂O + CO₂. The stoichiometric ratio of acid to base is
- a. 2:2
- b. 2:1
- c. 1:2
- d. 1:1
- The shape of the water molecule is
- a. Angular
- b. Tetrahedral
- c. Pyramidal
- d. Linear
- The volume occupied by 0.4 g of hydrogen gas at S.T.P. is (H = 1.00, Molar volume at S.T.P = 22.4 dm³)
- a. 2.24 dm³
- b. 4.48 dm³
- c. 22.4 dm³
- d. 8.96 dm³
- Which of the following will not decolourise bromine water?
- a. C₂H₆
- b. C₂H₄
- c. C₃H₄
- d. C₃H₆
- The gas that can be best collected by downward displacement of air
- a. Chlorine
- b. Carbon (IV) oxide
- c. Sulphur (IV) oxide
- d. Ammonia
- Which of the following properties of elements decreases generally across a period in the periodic table?
- a. Electronegativity
- b. Electron affinity
- c. Atomic radius
- d. Ionization energy
- If the electron configuration of an element is 1s²2s²2p⁶3s²3p⁶, it shows that it is a:
- a. Group II element
- b. Noble gas
- c. Group V element
- d. Group II element
- Cr₂O₇²⁻ + 14H⁺ + xe⁻ → 2Cr³⁺ + 7H₂O. The number of moles (x) of electrons in the above half-cell equation is:
- a. 2
- b. 4
- c. 7
- d. 6
- The volume occupied by 0.4 g of hydrogen gas at S.T.P. is (H = 1.00, molar volume at S.T.P = 22.4 dm³)
- a. 2.24 dm³
- b. 4.48 dm³
- c. 22.4 dm³
- d. 8.96 dm³
- A measure of the degree of disorderliness in a chemical system is known as:
- a. Enthalpy
- b. Free energy
- c. Entropy
- d. Activation energy
- H₂(g) + X₂(g) → 2HX(g), ΔH = positive. In the above reaction, a decrease in temperature will:
- a. Decrease the concentration of HX
- b. Favour the forward reaction
- c. Favour the yield HX
- d. Have no effect on the equilibrium position
- 3Fe(s) + 4H₂O(g) ⇌ Fe₃O₄ + 4H₂(g). The equilibrium constant K of the reaction above is represented as:
- a. [H₂]⁴/[H₂O]⁴
- b. [Fe]³[H₂O]⁴/[Fe₃O₄][H₂]⁴
- c. [Fe₃O₄][H₂]⁴/[Fe]³[H₂O]⁴
- d. [H₂]⁴/[H₂]⁴
- What is the quantity of electricity produced when a current of 0.5 A is passed for 5 hours 45 minutes (F = 96500)?
- a. 0.11F
- b. 0.22F
- c. 0.12F
- d. 1.1F
- The oxidation number of phosphorus in PO₄³⁻ is:
- a. +1
- b. +3
- c. +4
- d. +5
- Compounds that exist in two or more different structural forms which also differ in chemical or/and physical properties but possess the same molecular formula are said to exhibit:
- a. Isotopy
- b. Isomerism
- c. Polymerism
- d. Allotropy
- Consider the reaction represented by the following equation: H-C≡C-H H₂ → X H₂ → Y; X and Y respectively are:
- a. Ethene and ethane
- b. Ethane and ethene
- c. Ethyne and ethane
- d. Ethane and propene
- Compound N reacts with sodium metal to produce a gas that gives a “pop” sound with a burning splint. N also reacts with ethanol to give a sweet-smelling liquid. Compound N is an:
- a. Alkanol
- b. Alkanoate
- c. Alkane
- d. Alkanoic acid
- A solution of sodium trioxocarbonate (IV) contains 10.6 g in 250 cm³ of solution. Calculate the concentration of the solution. [Na₂CO₃ = 106.0]
- a. 0.4 mol dm⁻³
- b. 1.0 mol dm⁻³
- c. 10.6 mol dm⁻³
- d. 25.0 mol dm⁻³
- The IUPAC name of the compound:
CH₃ CH₃
| |
CH₃-CH-CH-CH₃
- a. 2,3-dimethylpent-2,3-one
- b. 3,4-dimethylpent-2-one
- c. 2,3-dimethylbutane
- d. 3,4-dimethylpentene
- The alkanoate CH₃CH₂COOC₂H₅ is the product of the reaction between:
- a. Ethanoic acid and ethanol
- b. Ethanoic acid and propanol
- c. Propanoic acid and ethanol
- d. Propanoic acid and propanol
- Filling the burette for titration involves these except:
- a. Wash with water
- b. Rinse with acid
- c. Eject air bubbles
- d. Read at eye level
- The change from the degree of unsaturation to saturation is called ___________ reaction.
- a. Substitution
- b. Addition
- c. Saturation
- d. Fermentation
THEORY QUESTIONS
- Explain the term “activation energy” and describe its significance in chemical reactions.
- Given the following reaction: 2KClO3(s)→2KCl(s)+3O2(g)2KClO₃ (s) \rightarrow 2KCl (s) + 3O₂ (g)
- (a) Calculate the volume of O₂ gas produced at S.T.P. when 12.25 g of KClO₃ is heated (K = 39, Cl = 35.5, O = 16).
- (b) Describe how you would confirm the gas produced is oxygen.
- Differentiate between a “molecular formula” and an “empirical formula” with examples.
- Explain the principle behind the separation of components in chromatography and mention one practical application of this technique.
- A compound contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen. Determine its empirical formula.
- Write balanced chemical equations for the following reactions:
- (a) Sodium reacting with water.
- (b) Hydrochloric acid reacting with sodium hydroxide.
- (c) Ethene reacting with bromine water.
- Discuss the importance of the pH scale in chemistry. Provide an example of a substance for each of the following pH ranges: acidic, neutral, and basic.
- Describe the process of electrolysis and its application in the extraction of metals, using aluminium as an example.
- Explain the concept of “catalysis” and distinguish between homogeneous and heterogeneous catalysis with examples.
- Calculate the enthalpy change (ΔH) for the following reaction, given the bond dissociation energies: H2(g)+Cl2(g)→2HCl(g)H₂ (g) + Cl₂ (g) \rightarrow 2HCl (g)
- Bond dissociation energies: H-H = 436 kJ/mol, Cl-Cl = 243 kJ/mol, H-Cl = 431 kJ/mol.
END OF EXAMINATION