Your School's Whatsapp Group - Join Us now
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

Chemistry WAEC Past Questions

Clear Selections
Change Subject Post a Question Check Syllabus Study My Bookmarks Past Questions Videos Watch Video Lessons Download App

Post UTME Past Questions Agent
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
1496

 Sketch a curve to show how the solubility of a gas varies with increasing temperature

View Answer & Discuss WAEC 1991
1497

The set-up shown in the diagram below was used to separate a drop of universal indicator into the constituent dyes using ethyl ethanoate as the solvent.

(a) What name is given to the separate strated in the diagram?

(b) State: (i) how many components are resolved in the separation;

(ii) the material normally used in laborary as the adsorbent medium;

(iii) which of the labels the point of application of the indicator.

View Answer & Discuss WAEC 1991
1498

(a)(i) Give two uses of chlorine.

(ii) State the action of chlorine on moist blue litmus paper

(b) Draw a labelled diagram for the laboratory preparation of a dry sample of chlorine

(c) State the type of reaction involved between chlorine and (i) aqueous iron (II) chloride;

(ii) propane. Write an equation for each reaction and name the product formed in (c)(ii).

(d) Consider the reactions the following equations: Cl\(_{2(g)}\) + 2Br\(^-_{(aq)}\) \(\to\) 2Cl\(^-_{(aq)}\) + Br\(_{2(g)}\)

F\(_{2(g)}\) + 2Cl\(^-_{(aq)}\) ---> 2F\(^-_{(aq)}\) + Cl\(_{2(g)}\)

From the equations, arrange bromine, chlorine and fluorine in increasing order of oxidizing ability. Give the reason for your answer.

View Answer & Discuss WAEC 1991
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Your School's Whatsapp Group - Join Us now
1499

(a) Name one gaseous hydrocarbon which is

(i) used for welding.

(ii) a major raw material for the plastic industry.

(b) Write the structural formula of the hydrocarbon in (a)(i) above. Name the process by which it can be converted to neoprene rubber.

(c) Potatoes contain a high proportion of carbohydrate.

(i) Give the main product formed when potatoes are dehydrated completely

(ii) Describe how you would convert potatoes to ethanol. State the reactions involved the process and write equation for the final stage of the conversion.

(iii) Draw a labelled diagram of the apparatus you  would use to obtain a sample of fairly pure ethanol from the product formed in (c)(ii) above. What is the name given to the technique?

View Answer & Discuss WAEC 1991
1500

(a) Give three differences between electrovalent compounds and covalent compounds 

(b) List two physical properties of metals which can be accounted for by their structure

(c) Thorium (Th) metal undergoes a reaction represented by the following equation:

\(^{234}_{90}Th \to X + ^{234}_{91}Pa\)

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

(ii) Balance the equation equation and hence identify X.

(iii) Name one equipment which can be used to detect X.

(iv) Sketch a curveto show the mass of given quantity of thorium will change over a long period of time.

(d) Y is a moderately reactive divalent found naturally in the combined state as the trioxocarbonate (IV) salt, YCO\(_3\) is decomposed by strong heat, state the steps you would use in extracting Y from the ore. Write equation to show the chemical processes involved.

View Answer & Discuss WAEC 1991
Start a Free Practice Test
 
Post UTME Past Questions Agent
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts