Chemistry Past Questions And Answers
The ionization energy is affected by the following factors except
- A. distance of the outermost electron(s) from the nucleus
- B. size of the positive nuclear charge
- C. ability to attract shared electron(s)
- D. screening effect of the inner electron(s)
Which of the following are properties of carbon (Il)oxide?
- A. The gas burns with a pale Blue flame forming carbon(IV)
- B. It is a good reducing agent
- C. All of the options
- D. the gass react with certain metals to form carbonyls
Vulcanization involves the removal of
- A) A monomer
- B) The single bond
- C) The double bond
- D) A polymer
Which of the following solids would not decompose on heating?
- A. Ammonium chloride
- B. Lead (i) trioxonitrate (V)
- C. Potassium trioxocarbonate (IV)
- D. Sodium hydrogen trioxocarbonate (IV)
What is the mass of 6.02 x 1024 atoms of magnesium? [Mg = 24, Avogadro constant = 6.02 x 1023 atoms mol-1]
- A. 240g
- B. 24 g
- C. 2.4g
- D. 0.24g
If 20 cm3 of distilled water is added to 80cm3 of 0. 50 mol dm-3 hydrochloric acid, the new concentration of the acid will be
- A. 0.10mol dm-3
- B. 0.20mol dm-3
- C. 0.40mol dm-3
- D. 2.00mol dm-3
(a)(i) State two general methods of preparing soluble salts.
(ii) Mention three pieces of apparatus required for determining the solubility of a salt at a given temperature.
(b) The solubilities of two salts represented as K and L were determined at various temperatures. The results are shown in the table below:
| Temperature (\(^o\)C) | 0 | 20 | 40 | 60 | 80 | 90 |
| Solubility of K (mol. dm\(^{-3}\)) | 0.38 | 0.46 | 0.54 | 0.62 | 0.69 | 0.73 |
| Solubility of L (mol. dm\(^{-3}\)) | 0.12 | 0.34 | 0.64 | 1.08 | 1.64 | 2.00 |
(i) Plot the solubility curves of K and L on the same graph. Use the curves to answer questions (ii) - (iv) below.
(ii) What is the solubility of K at 50°C?
(iii) At what temperature is the solubility of L equal to 1.0mol. dm\(^{-3}\)?
(iv) Over what temperature range is K more soluble that L?
(v) Given that the molar mass of L is 101g, determine whether a solution containing 3.4g of L per 250cm\(^3\) at 20°C is saturated or unsaturated.
View Discussion (0)WAEC 1997 THEORYPaul commended the churches in Macedonia for giving out of their freewill to the
- A. saints
- B. poor
- C. priests
- D. sick
CH3CH2Cl + KCN → CH3CH2CN + KCl CH3CH2Cl + KCN → CH3CH2CN + KCl In the reaction above, the cyanide is
- A. hydrophobic
- B. hydrophilic
- C. nucleophilic
- D. electrophilic
Organic Chemistry is the branch of Chemistry that deals with ______ and _______.
- A) Hydrogen and Oxygen
- B) Carbon and Carbon
- C) Carbon and Sulphur
- D) Carbon and Hydrogen