Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.
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Question 191:
RS(aq) + HF(aq) → RF(s) + HS(aq)
ΔH = -65.7 kj mol(-1).
From the equation above, it can be deduced that
Options:
A) the heat content of the reactants is lower than that of the products
B) the heat content of the reactants is higher than that of the products
C) the reaction is slow
D) a large amount of heat is absorbed
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The correct answer is B .
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Question 192: The structural component that makes detergent dissolve more quickly in water than soap is
Options:
A) -SO3- Na+
B) -COO-Na-
C) -SO4- Na+
D) -COO-K+
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The correct answer is A .
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Question 193: Which is the temperature of a given mass of a gas initially at 0°C and 9 atm, if the pressure is reduced to 3 atm at constant volume?
Options:
A) 91K
B) 182K
C) 273K
D) 819K
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The correct answer is A .
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Question 194: The boiling of fat and aqueous caustic soda is referred to as
Options:
A) hydrolysis
B) esterification
C) acidification
D) saponification
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The correct answer is D .
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Question 195: Which one of the following metals is not normally extracted by chemical reduction because of its position in the electrochemical series?
Options:
A) Copper
B) Iron
C) Lead
D) Potassium
E) Zinc
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The correct answer is D .
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Question 196: The gas that can best be collected by downward displacement of air is
Options:
A) Chlorine
B) Sulphur (IV) oxide
C) Ammonia
D) Carbon (IV) oxide
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The correct answer is C .
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Question 197: The knowledge of half-life can be used to
Options:
A) create an element
B) detect an element
C) split an element
D) irradiate an element
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The correct answer is A .
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Question 198: Alkanals can be differentiated from alkanones by reaction with?
Options:
A) 2,4-dinitrophenylhydrazine
B) hydrogen cyanide
C) sodium hydrogen sulphite
D) Tollen's reagent
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The correct answer is D .
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Question 199: Which of the following statements is FALSE?
Options:
A) Copper (ll) ion can be reduced to copper (l) ion by hydrochloric acid and zinc
B) Sodium metal dissolves in water giving oxygen
C) Nitrogen is insoluble in water
D) Carbondioxide is soluble in water
E) lead has a higher atomic weight than copper
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The correct answer is B .
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Question 200: On exposure to the atmosphere, a hydrated salt loses its water of crystallization to become anhydrous. This phenomenon is referred to as
Options:
A) efflorescence
B) diliquescence
C) hygroscopy
D) hydrolysis
Show Answer
The correct answer is A .