Symbols, Formulae and Simple Chemical Equations NDA Questions

NDA Chemistry

Symbols, Formulae and Simple Chemical Equations MCQ Questions


7.
Which of the following is a postulate of Dalton's Atomic Theory?
A.
Atoms can be created during chemical reactions
B.
Atoms of the same element can have different masses (isotopes)
C.
Atoms are divisible into protons, neutrons and electrons
D.
Atoms of the same element are identical in mass and properties; atoms of different elements differ in mass and properties
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ANSWER :
D. Atoms of the same element are identical in mass and properties; atoms of different elements differ in mass and properties
8.
Which postulate of Dalton's Atomic Theory explains the Law of Constant Proportions?
A.
Atoms of the same two elements always combine in the same fixed ratio to form a particular compound
B.
Atoms of the same element have identical masses
C.
Atoms are indivisible
D.
Atoms are rearranged during chemical reactions
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ANSWER :
A. Atoms of the same two elements always combine in the same fixed ratio to form a particular compound
9.
Which of the following is a limitation (failure) of Dalton's Atomic Theory?
A.
It could not explain chemical reactions
B.
It rejected the law of conservation of mass
C.
It could not explain the existence of isotopes (atoms of same element with different masses)
D.
It failed to describe atoms as building blocks of matter
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ANSWER :
C. It could not explain the existence of isotopes (atoms of same element with different masses)
10.
According to Dalton's Atomic Theory, what happens to atoms during a chemical reaction?
A.
New atoms of different elements are created
B.
Atoms are rearranged — old bonds break and new bonds form — but atoms themselves are neither created nor destroyed
C.
Atoms fuse together permanently and cannot be separated
D.
Atoms split into smaller particles
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ANSWER :
B. Atoms are rearranged — old bonds break and new bonds form — but atoms themselves are neither created nor destroyed
11.
The chemical symbol for an element is the abbreviated representation of its name. The symbol 'Na' for Sodium is derived from its:
A.
English name 'Sodium'
B.
Arabic name 'Soda'
C.
Latin name 'Natrium'
D.
Greek name 'Natrium'
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ANSWER :
C. Latin name 'Natrium'
12.
What is the correct chemical symbol for Potassium?
A.
Po
B.
Pt
C.
P
D.
K (from Latin 'Kalium')
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ANSWER :
D. K (from Latin 'Kalium')