Unified Tertiary Matriculation Examination · Physics and Chemistry

Chemical Systems, Bonding, Stoichiometry and Organic Chemistry

35 practice questions, each with the answer and an explanation.

Practise Chemical Systems, Bonding, Stoichiometry and Organic Chemistry now

Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 35 questions

  1. What is the complete ground-state electronic configuration of the iron(III) ion (Fe³⁺)? (Atomic number of Fe = 26)
  2. Across Period 3 of the Periodic Table, why is the first ionization energy of aluminum (Z = 13) slightly lower than that of magnesium (Z = 12)?
  3. According to Valence Shell Electron Pair Repulsion (VSEPR) theory, what is the geometric molecular shape and approximate bond angle of the ammonia molecule (NH₃)?
  4. Why is water (H₂O) a liquid at room temperature with a boiling point of 100°C, whereas hydrogen sulfide (H₂S) is a gas boiling at -60°C despite its higher molar mass?
  5. Calculate the mass of carbon dioxide (CO₂) gas liberated when 10.0 g of pure calcium carbonate (CaCO₃) is completely decomposed by heating. (Molar masses: Ca = 40, C = 12, O = 16 g/mol)
  6. A reaction mixture contains 4.0 g of hydrogen gas (H₂) and 32.0 g of oxygen gas (O₂). What is the maximum mass of water (H₂O) that can be produced? (Molar masses: H = 1, O = 16 g/mol)
  7. What volume of oxygen gas at standard temperature and pressure (STP) is evolved by the complete catalytic thermal decomposition of 24.5 g of potassium chlorate (KClO₃)? (Molar volume at STP = 22.4 dm³…
  8. An organic compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. If its relative molecular mass is 60.0 g/mol, what is its molecular formula? (Atomic masses: C = 12, H = 1, O = 16)
  9. Calculate the molar concentration (molarity) of a solution prepared by dissolving 10.6 g of anhydrous sodium carbonate (Na₂CO₃) in distilled water to make exactly 500 cm³ of solution. (Molar mass of N…
  10. What volume of 0.10 M hydrochloric acid (HCl) is required to completely neutralize 25.0 cm³ of 0.080 M sodium hydroxide (NaOH) solution during a volumetric titration?
  11. Determine the pH of a 0.0050 M aqueous solution of sulfuric acid (H₂SO₄), assuming complete electrolytic dissociation of both hydrogen ions.
  12. Which chemical combination forms an effective acidic buffer solution capable of resisting changes in pH upon minor additions of acid or base?
  13. The solubility product constant (Ksp) of silver chloride (AgCl) in water at 25°C is 1.0 × 10⁻¹⁰ mol²/dm⁶. What is the molar solubility of AgCl in pure water?
  14. For an endothermic chemical reaction, how does the enthalpy of the reaction products compare with that of the initial reactants?
  15. How does the addition of a positive chemical catalyst increase the rate of a chemical reaction without altering the overall enthalpy change (ΔH)?
  16. For the gaseous Haber synthesis: N₂(g) + 3H₂(g) <=> 2NH₃(g) (ΔH = -92 kJ/mol), which set of conditions favors the maximum equilibrium yield of ammonia according to Le Chatelier's principle?
  17. What is the oxidation state of chromium in the potassium dichromate compound (K₂Cr₂O₇)?
  18. In a standard Daniell voltaic cell, the half-cell potentials are: Zn²⁺/Zn (E° = -0.76 V) and Cu²⁺/Cu (E° = +0.34 V). What is the standard electromotive force (E°cell) of the cell?
  19. Calculate the mass of copper deposited at the cathode when an electric current of 2.0 A is passed through a copper(II) sulfate solution for 1,930 seconds. (Faraday constant F = 96,500 C/mol; Atomic ma…
  20. In the industrial extraction of aluminum by the Hall-Héroult electrolytic process, why is molten cryolite (Na₃AlF₆) added to purified alumina (Al₂O₃)?
  21. What solid chemical catalyst is employed in the catalytic converter chamber during the industrial Contact process for the manufacture of sulfuric acid?
  22. What is the systematic IUPAC name for the branched hydrocarbon with structural formula (CH₃)₂CH-CH₂-CH(CH₃)₂?
  23. Why does but-2-ene exhibit geometric (cis-trans) stereoisomerism, whereas but-1-ene does not?
  24. According to Markovnikov's rule, what is the major organic product formed when hydrogen bromide (HBr) undergoes electrophilic addition to propene (CH₃-CH=CH₂)?
  25. Which chemical test readily distinguishes an aliphatic aldehyde like ethanal from an aliphatic ketone like propanone?
  26. What sweet-smelling organic compound is formed when ethanoic acid is heated with ethanol in the presence of a few drops of concentrated sulfuric acid catalyst?
  27. What chemical reaction takes place during the traditional saponification process of manufacturing soap from palm oil?
  28. Which synthetic polymer is classified as a condensation polymer formed with the elimination of small water molecules during polymerization?
  29. Which gaseous atmospheric pollutant is the primary precursor responsible for the formation of industrial acid rain?
  30. The half-life of a first-order chemical reaction is 20 minutes. What percentage of the initial reactant concentration remains unreacted after 60 minutes?
  31. Calculate the standard enthalpy of combustion of propane (C₃H₈) given standard enthalpies of formation: ΔHf°[C₃H₈(g)] = -104 kJ/mol, ΔHf°[CO₂(g)] = -394 kJ/mol, ΔHf°[H₂O(l)] = -286 kJ/mol.
  32. What volume of dry hydrogen gas at STP is liberated when 4.8 g of pure magnesium metal reacts completely with excess dilute hydrochloric acid? (Molar mass of Mg = 24 g/mol; Molar volume of gas at STP…
  33. Why is sodium trioxocarbonate(IV) (Na₂CO₃) used in water treatment plants to soften permanent hard water containing dissolved calcium sulfate?
  34. Which pair of gases can both be collected in the laboratory by the upward displacement of air (downward delivery)?
  35. In the contact catalytic hydration of ethyne (acetylene) using dilute sulfuric acid and mercury(II) sulfate catalyst at 60°C, what carbonyl compound is the primary final product?

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