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Chemistry WAEC Past Questions

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1401

(a)(i) What type of reaction is involved in each of the conversion processes indicated as I to V below?

(ii) Name one isomer of glucose

(iii) Explain why palmwine becomes sour on prolonged exposure to air.

 

(b)(i) List the reagents and the reaction condition necessary for ethanoic acid to form an alkanoate.

(ii) Give two uses of alkanoates

(c)(i) What is the lUPAC name of the following compound?

(ii) Outline one chemical test to distinguish between methane and the compound in (c)(i) above.

(iii) Write an equation for the combustion of ethene in excess oxygen.

View Answer & Discuss WAEC 1998
1402

(a)(i) Define heat of neutralization

(ii) Give the reason why copper (II) chloride can be prepared by neutralization, unlike lead (II) chloride.

(b)(i) Describe in outline, the manufacture of trioxonitrate (V) acid by the catalytic oxidation of ammonia, giving equations where appropriate.

(ii) What are the products obtained when sodium tioxonitrate (V) is heated strongly?

 

(c) When powdered magnesium is heated to redness in a stream of nitrogen, magnesium nitride (Mg\(_3\)N\(_2\)) is formed.

(i) Write an equation for the reaction

(ii) Hence, calculate the amount (in mole) of magnesium nitride that can be obtained from 3.0g of magnesium [Mg = 24].

View Answer & Discuss WAEC 1998
1403

(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 Answer & Discuss WAEC 1998
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1404

(a) List two properties of alpha particles.

(b) X is an element which exists as an isotopic mixture containing 90% of \(^{39}_{19} X\) and 10% of \(^{41}_{19}X\).

(i) How many neutrons are present in the isotope \(^{41}_{19}X\)?

(ii) Calculate the mean relative atomic mass of X.

View Answer & Discuss WAEC 1997
1405

(a)(i) State the two main processes involved in the manufacture of oxygen from air

(ii) Name the type of chemical bonding which exists between oxygen atoms in a molecule of oxygen

(b) What term is used to describe the relationship between oxygen and ozone (O\(_3\))?

View Answer & Discuss WAEC 1997
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