Chemistry Past Questions And Answers
(a) (i) State Boyle's law.
(ii) Give the mathematical expression of Boyle's law.
(iii) Sketch the graphical representation of Boyle's law.
(b) A given mass of gas occupied 500 cm3 at 30°C and 6.5 x 104 Nm\(^{-2}\). Calculate the volume of the gas at s.t.p. [ Standard pressure = 1.01 x 105 Nm\(^{-2}\)]
(c) Explain why an inflated balloon expands in warm water.
(d)(i) What is meant by the term vapour density? (ii) Determine the vapour density of SO\(_{2}\). [ S = 32, O = 16 ]
(e)(i) Which of the following gases, SO\(_{2}\) and NH\(_{3}\) can be collected by I. upward delivery; II. downward delivery?
(ii) What would be the nature of the solution formed by dissolving each of the following substances in water separately. I. SO\(_{2}\) II. NH\(_{3}\)
(iii) State the property exhibited by SO\(_{2}\) and NH\(_{3}\) in the following equations:
I. 2H\(_{2}\)S\(_{(aq)}\) + SO\(_{2(g)}\) \(\to\) 3S\(_{(s)}\) + 2H\(_{2}\)O\(_{(/)}\)
II. 3CuO\(_{(s)}\) + 2NH\(_{3(g)}\) \(\to\) 3Cu\(_{(s)}\) + 3H\(_{2}\)O\(_{(/)}\) + N\(_{2(s)}\).
(f) State two alloys of tin.
(ii) Give one use of each of the alloys in (f)(i).
View Discussion (0)WAEC 2009 THEORYThe greater the difference? In electron negativity between bonded atoms, the
- A) lower the polarity of the bond
- B) higher the polarity of the bond
- C) weaker the bond
- D) higher the possibility of the substance formed being a molecule
Which of the following substance is an ore of iron?
- A. Bauxite
- B. Cassiterite
- C. Haematite
- D. Steel
The IUPAC nomenclature of the compound above is
- A) 2-bromo-3-chlorobutanol
- B) 3-bromo-2-chlorobutanol
- C) 3-chloro-2-bromobutanol
- D) 2-chloro-3-bromobutanol
(a)(i) What is an electrolyte?
(ii) Classify each of the following as strong electrolyte/weak, electrolyte/non-electrolyte. Potassium chloride; sodium ethanoate, aqueous ammonia; cane sugar
(b)(i) Write half-cell equations for the reactions in the Daniel cell .
(ii) Why is the Daniel cell classified as an electrochemical cell?
(iii) Give two other examples of electrochemical cell.
(c) Explain the following observations.
(i) Graphite conducts electricity, unlike most non-metals
(ii) In the electrolysis of copper (II) tetraoxosulphate (VI) solution, the blue colour fades with platinum electrodes while the colour intensity is unaffected with copper electrodes (equations required)
(iii) A solution of dry hydrogen chloride in methylbenzene (toluene) does not conduct electricity whereas hydrochloric acid does.
View Discussion (0)WAEC 1998 THEORYThe decolourization of purple colour of tetraoxomanganate (VII) ion is a test for
- A. alkenes
- B. alkanols
- C. alkanals
- D. alkanes
What is the function of sulphur (IV) oxide in the reaction represented by the following equation? SO2(aq) + 2H2S(g) → 3S (s) + 2H2O (l)
- A. Dehydrating agent
- B. Oxidising agent
- C. Bleaching agent
- D. Acid
An increase in temperature causes an increase in the pressure of a gas because?
- A. it decreases the number of collision between the molecules
- B. the molecules of the gas bombard the walls of the container more frequently
- C. it increases the number of collision between the molecules
- D. it causes the molecules to combine
Bubbing of carbon (IV) oxide into calcium hydroxide solution results in the formation of
- A. Ca(HCO3)2
- B. CaCO3
- C. CaO
- H2CO2
The noble gases owe their inactivity to
- A. Octet configuration
- B. Cyclic shape
- C. Hexagonal shape
- D. Obtuse configuration