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JAMB and WAEC Chemistry questions: Chemical combination

58 questions with answers and explanations. Tap an option to check yourself.

AllJAMBWAEC
All topicsAcids, bases and salts · 58Air · 37Atomic structure and bonding · 59Chemical combination · 58Chemical equilibrium · 37Chemistry and industry · 35Electrolysis · 41Energy changes · 38Environmental pollution · 32Kinetic theory of matter and gas laws · 45Metals and their compounds · 47Non-metals and their compounds · 45Organic compounds · 72Oxidation and reduction · 41Rates of chemical reaction · 38Separation of mixtures and purification · 42Solubility · 36Water · 39

  1. Question 21· Chemical combination· JAMB

    What mass of carbon(IV) oxide is produced when 6 g of carbon burns completely in oxygen? (C = 12, O = 16)

    Explanation and discussion

  2. Question 22· Chemical combination· JAMB

    What mass of sodium chloride is formed when 46 g of sodium reacts completely with chlorine? (Na = 23, Cl = 35.5)

    Explanation and discussion

  3. Question 23· Chemical combination· JAMB

    What is the mass of 22.4 dm³ of carbon(IV) oxide at s.t.p.? (C = 12, O = 16)

    Explanation and discussion

  4. Question 24· Chemical combination· JAMB

    Gay-Lussac's law states that gases react in volumes that are

    Explanation and discussion

  5. Question 25· Chemical combination· JAMB

    How many moles of oxygen atoms are in 0.5 mol of carbon(IV) oxide?

    Explanation and discussion

  6. Question 26· Chemical combination· JAMB

    How many moles of oxygen atoms are present in 0.5 mol of CaCO₃?

    Explanation and discussion

  7. Question 27· Chemical combination· WAEC

    A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Find its empirical formula. [C = 12, H = 1, O = 16]

    Explanation and discussion

  8. Question 28· Chemical combination· WAEC

    The relative molecular mass of CO₂ is (C = 12, O = 16)

    Explanation and discussion

  9. Question 29· Chemical combination· JAMB

    In the balanced equation aAl + bO₂ → cAl₂O₃, the values of a, b and c are

    Explanation and discussion

  10. Question 30· Chemical combination· WAEC

    The volume of 2 mol of an ideal gas at s.t.p. is

    Explanation and discussion

  11. Question 31· Chemical combination· WAEC

    The percentage of water of crystallisation in CuSO₄·5H₂O (Cu = 64, S = 32, O = 16, H = 1) is

    Explanation and discussion

  12. Question 32· Chemical combination· JAMB

    What volume of 0.1 mol/dm³ hydrochloric acid is needed to make 250 cm³ of 0.02 mol/dm³ acid?

    Explanation and discussion

  13. Question 33· Chemical combination· JAMB

    4 g of sodium hydroxide is dissolved in water to make 500 cm³ of solution. Find its concentration. (Na = 23, O = 16, H = 1)

    Explanation and discussion

  14. Question 34· Chemical combination· WAEC

    Avogadro's number of particles is

    Explanation and discussion

  15. Question 35· Chemical combination· JAMB

    The law of multiple proportions is illustrated by

    Explanation and discussion

  16. Question 36· Chemical combination· WAEC

    How many atoms are present in 0.5 mol of sulphur? [L = 6.02 × 10²³]

    Explanation and discussion

  17. Question 37· Chemical combination· JAMB

    The empirical formula of a compound containing 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass is: (C = 12, H = 1, O = 16)

    Explanation and discussion

  18. Question 38· Chemical combination· JAMB

    Find the percentage by mass of water of crystallisation in CuSO₄·5H₂O. (Cu = 64, S = 32, O = 16, H = 1)

    Explanation and discussion

  19. Question 39· Chemical combination· WAEC

    The formula of calcium chloride is

    Explanation and discussion

  20. Question 40· Chemical combination· JAMB

    In the reaction 2H₂(g) + O₂(g) → 2H₂O(l), what volume of oxygen reacts completely with 20 cm³ of hydrogen at the same temperature and pressure?

    Explanation and discussion

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