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Chemistry WAEC Past Questions

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Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
1451

(a) When MgSO\(_4\).XH\(_2\)O crystals were exposed to the atmosphere for several days, three  was a loss in mass

(i) What name is given to this phenomenon?

(ii) Give another example of a compound that exhibits this phenomenon

(b) If 0.50 mole of MgSO\(_4\).XH\(_2\)O has a mass of 123g. calculate the value of X. (H = 1, O = 16, Mg = 24, S = 32)

View Answer & Discuss WAEC 1994
1452

(a) Write an equation to show the action of strong heat on:

(i) potassium trioxonitrate (V):

(ii) sucrose.

(b) State two observations in respect of the reaction between granulated zinc and dilute tetraoxosulphate (VI) acid.

View Answer & Discuss WAEC 1994
1453

When ethane - 1,2-dioic acid is heated with concentrated tetraoxosulphate (VI) acid, a reaction represented by the following equation occurs:

(a) State the type of process involved in the reaction

(b) What is the basicity of ethane-1, s-dioic acid?

(c) List three differences in the chemical properties of the two oxides of carbon  produced during the reaction

View Answer & Discuss WAEC 1994
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1454

(a) State whether entropy increases or decreases during each of the following processes

(i) condensation of steam;

(ii) melting of wax;

(iii) dissolution of sugar in water;

(iv) abscas on charcoal.

 

(b) What deduction can be made in each case given that the value of the free energy change for a particular reaction is:

(i) zero;

ii) negative

View Answer & Discuss WAEC 1994
1455

Potassium trioxochlorate (V) undergoes thermal decomposition according to the fotpowing equation: 2KCIO\(_3\) \(\to\) 2KCI + 3O\(_2\)

(a) What substance could be used in the laboratory to in ease the rate of the reaction

(ii) absorb the oxygen produced

(b) Give the reason why an aqueous solution of silver trioxonitrate (V) gives a white precipitate with KCI but not with KClO\(_3\).
 

View Answer & Discuss WAEC 1994
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Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
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