Year :
2018
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
1 - 10 of 50 Questions
| # | Question | Ans |
|---|---|---|
| 1. |
Which of the following raw materials is used in the plastic industry? A. Ethene B. Methane C. Sulphur D. Hydrogen Detailed SolutionEthene is the most important organic chemical, by weight, that is manufactured. It is an important raw material for the production of plastics and antifreeze solutions as well as solvents. |
|
| 2. |
Which of the following organic compounds can undergo both addition and substitution reactions? A. Pentane B. Benzene C. Propane D. Hexane Detailed SolutionAn example of benzene addition reaction is the formation of cyclohexane by a mix of benzene vapour and hydrogen passed over nickel catalyst; while chlorobenzene is formed by substitution reaction. |
|
| 3. |
Which of the following equations represents a redox reaction? A. \(HNO_{{3}{(aq)}} + NaOH_{(aq)} \to NaNO_{{3}{(aq)}} + H_{2}O_{(l)}\) B. \(AgNO_{{3}{(aq)}}+KCl_{(aq)} \to AgCl_{(s)}+KNO_{{3}{(aq)}}\) C. \(CaCO_{{3}{(s)}} \to CaO_{(s)} + CO_{{2}{(g)}}\) D. \(2H_{2}S_{(s)} + SO_{{2}{(g)}} \to 2HO_{2} + 3S_{(g)}\) |
D |
| 4. |
The process of extraction of iron from its ore is A. decomposition B. oxidation C. reduction D. sublimation Detailed SolutionThe Iron is to to be gotten by the removal of oxygen from its ore, and this is called a reduction reaction. |
|
| 5. |
What is the solubility of a salt if 0.4g of it is obtained on evaporating 200\(cm^{3}\) of its saturated solution to dryness? A. 0.08\(gdm^{-3}\) B. 2.00\(gdm^{-3}\) C. 8.00\(gdm^{-3}\) D. 80.00\(gdm^{-3}\) Detailed Solution1000\(cm^{3}\) = 1\(dm^{3}\)200\(cm^{3}\) = 0.2\(dm^{3}\) ⇒ 0.2\(dm^{3}\) contains 0.4g hence, solubility of the salt which is the amount of the salt dissolvable in 1\(dm^{3}\) is \(\frac{0.4g}{0.2dm^{3}} = 2.0gdm^{-3}\) |
|
| 6. |
An acidic salt has A. double anions in its aqueous solution B. a single cation in its aqueous solution C. hydrogen ions in its aqueous solution D. hydrogen atoms in its aqueous solution Detailed SolutionAcid salts are salts whose aqueous solutions are acidic in character, implying that their aqueous solutions possess hydrogen ions. |
|
| 7. |
A reaction is endothermic if the A. reaction vessel feels cool during the reaction B. enthalpy change is negative C. bond forming energy exceeds bond breaking energy D. heat of formation of reactants exceeds heat of formation of products Detailed SolutionEndothermic reactions absorb heat from their surroundings during the reaction process. This means that in the course of the reaction the vessel being used in the reaction will be cool in the process. |
|
| 8. |
In which of the following compounds does hydrogen form ionic compounds? A. CH\(_{4}\) B. HCl C. NH\(_{3}\) D. NaH Detailed SolutionThe bonding between a non-metal and a metal is an ionic bonding. In metal hydrides, Hydrogen takes on the ionic charge of -1, hence forming an ionic bond with the metals. |
|
| 9. |
An organic compound has the empirical formula \(CH_{2}\). If its molar mass is 42\(gmol^{-1}\), what is its molecular formula? (C = 12.0, H = 1.0) A. \(C_{2}H_{4}\) B. \(C_{3}H_{4}\) C. \(C_{3}H_{6}\) D. \(C_{4}H_{8}\) Detailed SolutionGiven the molecular formula, \(CH_{2}\).The empirical formula will be \((CH_{2})n\)= 42 \((12+(2\times1))n =42\) ⇒ \(14n =42\) n = 3, hence the empirical formula is \(C_{3}H_{6}\) |
|
| 10. |
Consider the following reaction equation: \(Br_{2} + 2KI \to 2KBr + I_{2}\). Bromine is acting as A. an oxidizing agent B. a reducing agent C. an acid D. a base |
A |
| 1. |
Which of the following raw materials is used in the plastic industry? A. Ethene B. Methane C. Sulphur D. Hydrogen Detailed SolutionEthene is the most important organic chemical, by weight, that is manufactured. It is an important raw material for the production of plastics and antifreeze solutions as well as solvents. |
|
| 2. |
Which of the following organic compounds can undergo both addition and substitution reactions? A. Pentane B. Benzene C. Propane D. Hexane Detailed SolutionAn example of benzene addition reaction is the formation of cyclohexane by a mix of benzene vapour and hydrogen passed over nickel catalyst; while chlorobenzene is formed by substitution reaction. |
|
| 3. |
Which of the following equations represents a redox reaction? A. \(HNO_{{3}{(aq)}} + NaOH_{(aq)} \to NaNO_{{3}{(aq)}} + H_{2}O_{(l)}\) B. \(AgNO_{{3}{(aq)}}+KCl_{(aq)} \to AgCl_{(s)}+KNO_{{3}{(aq)}}\) C. \(CaCO_{{3}{(s)}} \to CaO_{(s)} + CO_{{2}{(g)}}\) D. \(2H_{2}S_{(s)} + SO_{{2}{(g)}} \to 2HO_{2} + 3S_{(g)}\) |
D |
| 4. |
The process of extraction of iron from its ore is A. decomposition B. oxidation C. reduction D. sublimation Detailed SolutionThe Iron is to to be gotten by the removal of oxygen from its ore, and this is called a reduction reaction. |
|
| 5. |
What is the solubility of a salt if 0.4g of it is obtained on evaporating 200\(cm^{3}\) of its saturated solution to dryness? A. 0.08\(gdm^{-3}\) B. 2.00\(gdm^{-3}\) C. 8.00\(gdm^{-3}\) D. 80.00\(gdm^{-3}\) Detailed Solution1000\(cm^{3}\) = 1\(dm^{3}\)200\(cm^{3}\) = 0.2\(dm^{3}\) ⇒ 0.2\(dm^{3}\) contains 0.4g hence, solubility of the salt which is the amount of the salt dissolvable in 1\(dm^{3}\) is \(\frac{0.4g}{0.2dm^{3}} = 2.0gdm^{-3}\) |
| 6. |
An acidic salt has A. double anions in its aqueous solution B. a single cation in its aqueous solution C. hydrogen ions in its aqueous solution D. hydrogen atoms in its aqueous solution Detailed SolutionAcid salts are salts whose aqueous solutions are acidic in character, implying that their aqueous solutions possess hydrogen ions. |
|
| 7. |
A reaction is endothermic if the A. reaction vessel feels cool during the reaction B. enthalpy change is negative C. bond forming energy exceeds bond breaking energy D. heat of formation of reactants exceeds heat of formation of products Detailed SolutionEndothermic reactions absorb heat from their surroundings during the reaction process. This means that in the course of the reaction the vessel being used in the reaction will be cool in the process. |
|
| 8. |
In which of the following compounds does hydrogen form ionic compounds? A. CH\(_{4}\) B. HCl C. NH\(_{3}\) D. NaH Detailed SolutionThe bonding between a non-metal and a metal is an ionic bonding. In metal hydrides, Hydrogen takes on the ionic charge of -1, hence forming an ionic bond with the metals. |
|
| 9. |
An organic compound has the empirical formula \(CH_{2}\). If its molar mass is 42\(gmol^{-1}\), what is its molecular formula? (C = 12.0, H = 1.0) A. \(C_{2}H_{4}\) B. \(C_{3}H_{4}\) C. \(C_{3}H_{6}\) D. \(C_{4}H_{8}\) Detailed SolutionGiven the molecular formula, \(CH_{2}\).The empirical formula will be \((CH_{2})n\)= 42 \((12+(2\times1))n =42\) ⇒ \(14n =42\) n = 3, hence the empirical formula is \(C_{3}H_{6}\) |
|
| 10. |
Consider the following reaction equation: \(Br_{2} + 2KI \to 2KBr + I_{2}\). Bromine is acting as A. an oxidizing agent B. a reducing agent C. an acid D. a base |
A |