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 491:
Calculate the volume in cm3 of oxygen evolved at s.t.p when a current of 5A is passed through acidified water for 193s?
[F = 96500 C mol1. Molar volume of a gas at s.t.p = 22.4dm3]
Options:
A) 0.056dm3
B) 0.224dm3
C) 224.000dm3
D) 56.000dm3
Show Answer
The correct answer is A .
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Question 492:
MnO-4(aq) + Y + 5Fe2+(aq) → Mn2+(aq) + 5Fe2+(aq) + 4H2O(l)
In the equation above, Y is
Options:
A) 5H+(aq)
B) 4H+(aq)
C) 10H+(aq)
D) 8H+(aq)
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The correct answer is D .
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Question 493:
A balanced chemical equation obeys the law of
Options:
A) conservation of mass
B) definite proportions
C) multiple proportions
D) conservation of energy
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The correct answer is A .
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Question 494: How many grams of bromine will be required to completely react with 10 g of propyne?(C = 12, H = 1, Br = 80)
Options:
A) 20 g
B) 40 g
C) 60 g
D) 80 g
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The correct answer is D .
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Question 495: When a pressure cooker is half filled with water, and heated to boiling point, then the pressure inside the cooker will?
Options:
A) decrease, since only a fraction of the water molecules has changed to vapour
B) remain constant, because the total number of water molecules has not changed
C) increase, because the water molecules can now reach every part of the sealed tube
D) decrease, since water boils under reduced pressure
E) increase, because the water vapour molecules now strike the walls of the tube more frequently because of their increased velocity
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The correct answer is E .
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Question 496:
The functional groups present in the compound above are
Options:
A) Alkene and halo-group
B) Hydroxyl and chloro-group
C) Alkene and chloro-group
D) Hydroxyl and halo-group
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The correct answer is B .
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Question 497: A difference between chemical and physical change is that in a chemical change
Options:
A) oxygen is consumed
B) heat is supplied
C) the reversible process occurs
D) a new substance is formed
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The correct answer is D .
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Question 498:
Which of the following are mixtures?
i. Petroleum
ii. Rubber latex
iii. Vulcanizer's solution
iv. Carbon (II) sulphide
Options:
A) i, ii and iii
B) i, ii and iv
C) i and ii only
D) i and iv
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The correct answer is A .
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Question 499:
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 C .
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Question 500: A carcinogenic substance is
Options:
A) asbestos dust
B) sawdust
C) nitrogen (II) oxide
D) carbon (II) oxide
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The correct answer is A .