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 21:
Which of the following alkanes has a straight-chain structure?
Options:
A) Cyclopentane (C5H10)
B) Isobutane (C4H10)
C) 2 - methyl propane (C4H10)
D) Pentane (C5H12)
Show Answer
The correct answer is D .
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Question 22:
What are the possible oxidation numbers of an element if its atomic number is 17?
Options:
A) -1 and 7
B) -1 and 6
C) -3 and 5
D) -2 and 6
Show Answer
The correct answer is A .
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Question 23: Three drops of a 1.0 mol dm-3 solution of HCl was added to 20 cm3 of a solution of pH6.4. The pH of the resulting solution will be
Options:
A) close to that of pure water
B) less than 6.4
C) greater than 6.4
D) unaltered
Show Answer
The correct answer is B .
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Question 24: The pollution from petroleum spillage in rivers and lakes can best be dispersed by
Options:
A) Pouring detergents
B) Passing of ships through the area
C) Pouring organic solvents
D) Evaporation
Show Answer
The correct answer is A .
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Question 25: The electron configuration of two elements with similar chemical properties are represented by?
Options:
A) 1s22s22p5 and 1s22s22p4
B) 1s22s22p4 and 1s22s22p63s1
C) 1s22s22p63s1 and 1s22s1
D) 1s22s22p4 and 1s22s1
Show Answer
The correct answer is C .
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Question 26:
The only metal that is anti-bacterial is?
Options:
A) Iron
B) Sodium
C) Alluminium
D) Copper
Show Answer
The correct answer is D .
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Question 27: When a piece of charcoal enclosed in a cylinder containing air is ignited
Options:
A) the toatl volume of air is increased
B) the relative amount of oxygen present is increased
C) the relative amount of nitrogen present is decreased
D) the relative amount of carbondioxide present is increased
E) the ratio of oxygen to nitrogen in the system is increased
Show Answer
The correct answer is D .
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Question 28: The solubility curve shows the variation of solute concentration with
Options:
A) volume
B) temperature
C) vapour density
D) pressure
Show Answer
The correct answer is B .
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Question 29: A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, Find the molecular formula [H = 1, C = 12, O = 16)
Options:
A) CH2O
B) C3H6O3
C) C6H12O6
D) C6H12O3
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The correct answer is C .
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Question 30: A compound contains 40.0% C, 6.7% H 53.3% O. If the molecular mass of the compound is 180, its molecular formula is [C =12, H =1,O]
Options:
A) CH2O
B) C3H6O3
C) C6H6O3
D) C6H12O6
Show Answer
The correct answer is D .