Year :
2019
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
11 - 20 of 50 Questions
| # | Question | Ans |
|---|---|---|
| 11. |
How many moles of carbon(iv)oxide contains 16.0g of oxygen?[ C = 12.0, O = 16.0 ] A. 0.20 mol B. 0.25 mol C. 0.40 mol D. 0.50 mol Detailed Solution1 Mole of carbon(iv)oxide contains 32g of Oxygen: 0.5 Mole of carbon(iv)oxide contains 16g of Oxygen |
|
| 12. |
Stoichiometry is based on the law? A. multiple proportion B. constant composition C. conservation of energy D. conservation of mass Detailed SolutionThe principles of stoichiometry are based upon the law of conservation of mass. Matter can neither be created nor destroyed, so the mass of every element present in the product(s) of a chemical reaction must be equal to the mass of each and every element present in the reactant(s). |
|
| 13. |
What is the percentage by mass of H in CH3COOH A. 1.7% B. 5.0% C. 6.7% D. 7.1% |
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| 14. |
Which of the following compounds has coordinate bonds in its structure? A. Al\(_2\)Cl\(_6\) B. MgCl\(_2\) C. AgCl D. NaCl Detailed SolutionAluminum chloride (Al2Cl6) has coordinate dative bonding |
|
| 15. |
The name of the compound CH\(_3\)C(CH\(_3\))CH\(_2\)CH\(_2\)CH\(_3\) A. 2 - methyl butane B. 2,2 - dimethyl butane C. 2 - methyl pentane D. 2,2 - dimethyl pentane Detailed Solution- The longest chain has five carbon atoms i.e PENT- with two methyl attached to the second carbon atom |
|
| 16. |
The properties of a good primary standard include the following except? A. High molecular mass B. low molecular mass C. high degree of purity D. readily available Detailed SolutionProperties of a good standard solution |
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| 17. |
What is the solubility of a salt X at 25ºC if the saturated solution of the salt contains 0.28g in 100cm\(^3\) of the solution in mol\dm\(^3\)? [ X = 56.0g ] A. 0.05 B. 0.10 C. 2.60 D. 2.80 Detailed Solution(mass / molar mass) X (1000 / vol )(0.28 / 56.0) X (1000 / 100 ) = 2.8 / 56 = 0.05 mol\dm\(^3\) |
|
| 18. |
Vinegar is an aqueous solution of? A. Hydrochloric acid B. ethanedioc acid C. ethanoic acid D. hydrofluoric acid Detailed SolutionVinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. |
|
| 19. |
Which of the following solutions containing one mole per dm\(^3\) of the compound would have the lowest PH? A. ethanoic acid B. hydrochloric acid C. sodium chloride D. sodium hydrogentrioxocarbonate(iv) Detailed SolutionLow PH means strongly acidic cause acidity increases with decreasing PH values.Example is Hydrochloric Acid |
|
| 20. |
A sample of air was bubbled into water. The PH of the water slowly changed from 7 to 6. Which of the following gases in the samples caused the change? A. carbon(iv)oxide B. carbon(ii)oxide C. nitrogen D. oxygen Detailed SolutionAn acid gas is any gaseous compound which, when dissolved in water, will form an acidic solution The most common acid gases are hydrogen sulfide (H2S) and carbon dioxide (CO2) gases |
| 11. |
How many moles of carbon(iv)oxide contains 16.0g of oxygen?[ C = 12.0, O = 16.0 ] A. 0.20 mol B. 0.25 mol C. 0.40 mol D. 0.50 mol Detailed Solution1 Mole of carbon(iv)oxide contains 32g of Oxygen: 0.5 Mole of carbon(iv)oxide contains 16g of Oxygen |
|
| 12. |
Stoichiometry is based on the law? A. multiple proportion B. constant composition C. conservation of energy D. conservation of mass Detailed SolutionThe principles of stoichiometry are based upon the law of conservation of mass. Matter can neither be created nor destroyed, so the mass of every element present in the product(s) of a chemical reaction must be equal to the mass of each and every element present in the reactant(s). |
|
| 13. |
What is the percentage by mass of H in CH3COOH A. 1.7% B. 5.0% C. 6.7% D. 7.1% |
|
| 14. |
Which of the following compounds has coordinate bonds in its structure? A. Al\(_2\)Cl\(_6\) B. MgCl\(_2\) C. AgCl D. NaCl Detailed SolutionAluminum chloride (Al2Cl6) has coordinate dative bonding |
|
| 15. |
The name of the compound CH\(_3\)C(CH\(_3\))CH\(_2\)CH\(_2\)CH\(_3\) A. 2 - methyl butane B. 2,2 - dimethyl butane C. 2 - methyl pentane D. 2,2 - dimethyl pentane Detailed Solution- The longest chain has five carbon atoms i.e PENT- with two methyl attached to the second carbon atom |
| 16. |
The properties of a good primary standard include the following except? A. High molecular mass B. low molecular mass C. high degree of purity D. readily available Detailed SolutionProperties of a good standard solution |
|
| 17. |
What is the solubility of a salt X at 25ºC if the saturated solution of the salt contains 0.28g in 100cm\(^3\) of the solution in mol\dm\(^3\)? [ X = 56.0g ] A. 0.05 B. 0.10 C. 2.60 D. 2.80 Detailed Solution(mass / molar mass) X (1000 / vol )(0.28 / 56.0) X (1000 / 100 ) = 2.8 / 56 = 0.05 mol\dm\(^3\) |
|
| 18. |
Vinegar is an aqueous solution of? A. Hydrochloric acid B. ethanedioc acid C. ethanoic acid D. hydrofluoric acid Detailed SolutionVinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. |
|
| 19. |
Which of the following solutions containing one mole per dm\(^3\) of the compound would have the lowest PH? A. ethanoic acid B. hydrochloric acid C. sodium chloride D. sodium hydrogentrioxocarbonate(iv) Detailed SolutionLow PH means strongly acidic cause acidity increases with decreasing PH values.Example is Hydrochloric Acid |
|
| 20. |
A sample of air was bubbled into water. The PH of the water slowly changed from 7 to 6. Which of the following gases in the samples caused the change? A. carbon(iv)oxide B. carbon(ii)oxide C. nitrogen D. oxygen Detailed SolutionAn acid gas is any gaseous compound which, when dissolved in water, will form an acidic solution The most common acid gases are hydrogen sulfide (H2S) and carbon dioxide (CO2) gases |