Past Questions And Answers
(a) Atoms of four non-metallic elements in the same group of the periodic table are arranged in order of increasing atomic radius as R < T < W < X. Which of the elements
(i) would readily lose electron(s) from the outermost shell;
(ii) is most electronegative;
(iii) would T displace from aqueous solution;
(iv) is at the top of the group?
(b) The following table shows the electronic configuration of two elements Y and Z.
Element | Electronic Configuration |
| Y | 1s\(^2\) 2s\(^2\) 2p\(^5\) |
| Z | 1s\(^2\) 2s\(^2\) 2p\(^5\) 3s\(^1\) |
(i) Name the I. group to which Y belongs II. period to which Z belongs.
(ii) What is the number of protons present in an atom of Z?
(iii) How many unpaired electrons are in an atom of Y?
(iv) Write the formula of the compound formed between Y and Z
(c) Name the type of bond(s) that exist(s) in each of the following compounds.
(i) CaCl\(_2\); (ii) NH\(_4\)Cl; CCl\(_4\)
(d) Describe how the conductance of a molar solution of ammonia compares to that of sodium hydroxide solution.
(e) State the type of reaction illustrated by each of the following equations:
(i) CH\(_3\)CH\(_2\)OH\(_{(/)}\) + CH\(_3\)COOH\(_{(aq)}\) \(\rightleftharpoons\) CH\(_3\)COOC\(_2\)H\(_5\)\(_{(/)}\) + H\(_2\)O\(_{(/)}\)
(ii) H\(^+_{(aq)}\) + OH\(^-_{(aq)}\) \(\to\) H\(_2\)O
(f) Determine the volume of the residual gas when 20.0cm\(^3\) of hydrogen was sparked with 15.0cm\(^3\) of oxygen and the resulting mixture cooled to room temperature.
View Discussion (0)WAEC 2009 THEORYFor an economy which last year produced only two commodities X and Y, the real cost of the quantity of X which it produced can be measured by the?
- A. amount of X it could not produced
- B. amount of Y it produced
- C. total amount of Y it could have produced
- D. extra amount of Y it could have produced
The rate of decomposition of organisms is faster in the tropical rain forest than in other biomes because
- A. of the relatively constant daylight
- B. there are more plants per square feet
- C. of abundance of water
- D. of constant cool temperature
---------- is the process by which the food is broken down in the body.
- (a) eating system
- (b)constipation
- (c)digestion
- (d)respiration
(a) Name three main parts of the human brain
(b) State the functions of the following:
(i) Cerebrum
(ii) Hypothalamus
(iii) Medulla Oblongata.
(c)(i) List three organs of a higher plant that can respond to stimulus
(ii) What is tactic movement?
(d) Explain the following terms, giving one example in each case:
(I) Phototaxis
(ii) Hydrotaxis
(iii) Chemotaxis.
View Discussion (0)WAEC 2003 THEORYWhich of the animal product is used in the production of buttons?
- A. Skin
- B. Fur
- C. Bone
- D. Hom
An amphoteric oxide is an
- A) amorphorous oxide of a metal
- B) amorphorous oxide of a non-metal
- C) Oxide that is insoluble in water
- D) Oxide that behaves as a base as well as an acid
(a) Define the following in
(i) elimination
(ii) excretion
(iii) secretion.
(b) Describe the digestion of boiled fish in the gut of humans
(c) Make a diagram 8cm - 10am long of a longitudinal section of a villus and label fully.
View Discussion (0)WAEC 2014 THEORYIf a reaction is said to be exothermic, which of the following statements is a correct deduction from the information?
- A. the reaction vessel gets hotter as the reaction proceeds
- B. ΔH for the reaction is positive
- C. the rate of the reaction increases with time
- D. the activation energy of the reaction is high
Which of the following kings said, 'Behold your gods, O Israel, who brought you up out of the land of Egypt?
- A. Rehoboam
- B. Ahab
- C. Jeroboam
- D. Zedekiah