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 431: Phosphorus burns in oxygen according to the equation P4 + 502 → P4O10. How many litres of oxygen will be required at S.T.P for complete oxidation of 12.4g of phosphorus? [P = 31,O = 16 and molar volume of a gas at S.T.P = 22.4 litres]
Options:
A) 5. 20
B) 11. 20
C) 2. 24
D) 20. 20
E) 6. 20
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The correct answer is B .
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Question 432: Which of the following statements is NOT correct?
Options:
A) The average kinetic energy of a gas is directly proportional to its temperature
B) At constant tempearture, the volume of a gas increases as the pressure increases
C) The pressure of a gas is inversely proportional to its volume
D) The temperature of a gas is directly proportional to its volume
E) The collisions of molecules with each other are inelastic
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The correct answer is B .
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Question 433: The function of zinc electrode in a galvanic cells is that it
Options:
A) undergoes reduction
B) serves as the positive electrode
C) production electons
D) uses up electrons
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The correct answer is C .
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Question 434:
An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.
The molecular formula of X is
Options:
A) C12H22O11
B) C6H12O6
C) C3H6O 3
D) C7H14O7
E) C12H6O4
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The correct answer is B .
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Question 435: Bronze is an alloy of?
Options:
A) silver and copper
B) silver and gold
C) copper and nickle
D) copper and zinc
E) copper and tin
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The correct answer is E .
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Question 436: The haloalkanes used in dry-cleaning industries are
Options:
A) trichloromethane and tetrachloromethane
B) chloroethene and dichloroethene
C) trichloroethene and tetrachloroethene
D) chloroethane and dichloroethene
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The correct answer is A .
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Question 437:
The nucleus of an atom consists of?
Options:
A) Electrons and neutrons
B) Electrons and protons
C) Protons and neutrons
D) None of the above
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The correct answer is C .
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Question 438:
The set-up above would be useful for determining the amount of
Options:
A) oxygen in air
B) water vapour in air
C) CO2 in air
D) arygen in air
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The correct answer is B .
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Question 439: When iron is exposed to moist air, it gradually rusts. This is due to the formation of
Options:
A) hydrate iron (III) oxide
B) anhydrous iron (III) oxide
C) anhydrous iron (II) oxide
D) hydrate iron (II) oxide
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The correct answer is A .
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Question 440: Liquid X, reacts with sodium trioxocarbonate (IV) (Na2CO3) to give a gas which turns calcium chloride solution milky X is
Options:
A) Na2SO4(aq)
B) Kl (aq)
C) an alkali
D) an acid
E) a hydrocarbon
Show Answer
The correct answer is D .