Chemistry, 2020, JAMB Exam, Exam, Paper 1 | Objectives

Paper Info

Year :

2020

Title :

Chemistry

Exam :

JAMB Exam

Paper 1 | Objectives

31 - 40 of 40 Questions

#	Question	Ans
31.	The chlorinated alkane often used industrially to remove grease is? A. Tetrachloromethane B. Chloromethane C. Trichloromethane D. Dichloromethane Show Content Detailed Solution Tetrachloromethane ( carbon tetrachloride) is an effective solvent within the chemical industry and is used to clean machinery and electrical equipment. I.e as a solvent for oils, fats, lacquers, varnishes, rubber waxes, and resins, and as a grain fumigant. There is an explanation video available below.	A
32.	What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen? A. 8.0g B. 16.0g C. 36.0g D. 72.0g Show Content Detailed Solution 2H\(_2\) + O\(_2\) ⇒ 2H\(_2\)O From the equation: 4g of Hydrogen produces 36g of water : 8g of Hydrogen will produce 72g of water There is an explanation video available below.	D
33.	Proteins in acid solution undergo? A. Substitution B. Fermentation C. Hydrolysis D. Polymerisation Show Content Detailed Solution Acid hydrolysis refers to a hydrolysis reaction occurring under acidic conditions. Acid hydrolysis of a protein breaks the polymer down into its constituent amino acids. There is an explanation video available below.	C
34.	The general formula for the Alkanals is? A. R\(_2\)CO B. RCHO C. ROH D. RCOOR Show Content Detailed Solution Alkanals or Aldehydes have the general formula RCHO while Alkanones or Ketones have the general formula RCOR'. Where R and R' may be alkyl or aryl groups. There is an explanation video available below.	B
35.	When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes? A. Bipolar B. Negatively charged C. Positively charged D. Neutral Show Content Detailed Solution When these cathode rays are deflected onto an electrode of an electrometer, the instrument measured a negative charge. The rays tested also were deflected by application of an electric field. There is an explanation video available below.	B
36.	When a solid substance disappears completely as a gas on heating, the substance is said to have undergone? A. Sublimation B. Crystallization C. Distillation D. Evaporation Show Content Detailed Solution Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state. There is an explanation video available below.	A
37.	An electron can be added to a halogen atom to form a halide ion with? A. 8 valence electrons B. 7 valence electrons C. 2 valence electrons D. 3 valence electrons Show Content Detailed Solution A halide ion is a halogen atom bearing a negative charge (which is an anion with a charge of -1). The halide anions are fluoride (F−), chloride (Cl−), bromide (Br−), iodide (I−) and astatide (At−). There is an explanation video available below.	A
38.	Aluminum hydroxide is used in the dyeing industry as a? A. Dye B. Dispersant C. Salt D. Mordant Show Content Detailed Solution Aluminum hydroxide is also used as a mordant in dyeing. There is an explanation video available below.	D
39.	The most important element on the earth's crust is? A. Nitrogen B. Hydrogen C. Oxygen D. Fluorine Show Content Detailed Solution Oxygen, O2, is by far the most abundant element in earth's crust at 46.6 percent, nearly half of the mass of the crust. There is an explanation video available below.	C
40.	To obtain pure carbon(ii)oxide from its mixture with carbon(iv)oxide, the mixture should be? A. Passed over heated copper(ii)oxide B. Bubbled through water C. Bubbled through conc H\(_2\)SO\(_4\) D. Bubbled through conc NAOH Show Content Detailed Solution carbon(ii)oxide is prepared from carbon(iv)oxide by passing the latter through red-hot carbon and the unchanged CO\(_2\) is removed when the mixture of the gases through conc NAOH. There is an explanation video available below.	D

31.	The chlorinated alkane often used industrially to remove grease is? A. Tetrachloromethane B. Chloromethane C. Trichloromethane D. Dichloromethane Show Content Detailed Solution Tetrachloromethane ( carbon tetrachloride) is an effective solvent within the chemical industry and is used to clean machinery and electrical equipment. I.e as a solvent for oils, fats, lacquers, varnishes, rubber waxes, and resins, and as a grain fumigant. There is an explanation video available below.	A
32.	What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen? A. 8.0g B. 16.0g C. 36.0g D. 72.0g Show Content Detailed Solution 2H\(_2\) + O\(_2\) ⇒ 2H\(_2\)O From the equation: 4g of Hydrogen produces 36g of water : 8g of Hydrogen will produce 72g of water There is an explanation video available below.	D
33.	Proteins in acid solution undergo? A. Substitution B. Fermentation C. Hydrolysis D. Polymerisation Show Content Detailed Solution Acid hydrolysis refers to a hydrolysis reaction occurring under acidic conditions. Acid hydrolysis of a protein breaks the polymer down into its constituent amino acids. There is an explanation video available below.	C
34.	The general formula for the Alkanals is? A. R\(_2\)CO B. RCHO C. ROH D. RCOOR Show Content Detailed Solution Alkanals or Aldehydes have the general formula RCHO while Alkanones or Ketones have the general formula RCOR'. Where R and R' may be alkyl or aryl groups. There is an explanation video available below.	B
35.	When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes? A. Bipolar B. Negatively charged C. Positively charged D. Neutral Show Content Detailed Solution When these cathode rays are deflected onto an electrode of an electrometer, the instrument measured a negative charge. The rays tested also were deflected by application of an electric field. There is an explanation video available below.	B

36.	When a solid substance disappears completely as a gas on heating, the substance is said to have undergone? A. Sublimation B. Crystallization C. Distillation D. Evaporation Show Content Detailed Solution Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state. There is an explanation video available below.	A
37.	An electron can be added to a halogen atom to form a halide ion with? A. 8 valence electrons B. 7 valence electrons C. 2 valence electrons D. 3 valence electrons Show Content Detailed Solution A halide ion is a halogen atom bearing a negative charge (which is an anion with a charge of -1). The halide anions are fluoride (F−), chloride (Cl−), bromide (Br−), iodide (I−) and astatide (At−). There is an explanation video available below.	A
38.	Aluminum hydroxide is used in the dyeing industry as a? A. Dye B. Dispersant C. Salt D. Mordant Show Content Detailed Solution Aluminum hydroxide is also used as a mordant in dyeing. There is an explanation video available below.	D
39.	The most important element on the earth's crust is? A. Nitrogen B. Hydrogen C. Oxygen D. Fluorine Show Content Detailed Solution Oxygen, O2, is by far the most abundant element in earth's crust at 46.6 percent, nearly half of the mass of the crust. There is an explanation video available below.	C
40.	To obtain pure carbon(ii)oxide from its mixture with carbon(iv)oxide, the mixture should be? A. Passed over heated copper(ii)oxide B. Bubbled through water C. Bubbled through conc H\(_2\)SO\(_4\) D. Bubbled through conc NAOH Show Content Detailed Solution carbon(ii)oxide is prepared from carbon(iv)oxide by passing the latter through red-hot carbon and the unchanged CO\(_2\) is removed when the mixture of the gases through conc NAOH. There is an explanation video available below.	D