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9th CBSE
IMPORTANT
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John Dalton's most outstanding contribution to chemistry was a scientifically grounded atomic theory. He even supplemented his atomic theory with theoretical values of atomic masses and atomic sizes which were found to be incorrect. This revealed discrepancy between his enthusiasm in chemistry and his inadequate training. He even did not consider Aristotle's suggestion of divisibility of atom.

What value can we learn from Dalton's supplementation of his atomic theory with theoretical values of atomic masses and atomic sizes of elements, which were found to be incorrect?

Important Questions on Atoms and Molecules

HARD
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Practice Questions>Q 1

John Dalton's most outstanding contribution to chemistry was a scientifically grounded atomic theory. He even supplemented his atomic theory with theoretical values of atomic masses and atomic sizes which were found to be incorrect. This revealed discrepancy between his enthusiasm in chemistry and his inadequate training. He even did not consider Aristotle's suggestion of divisibility of atom.

What value can we learn from Dalton's non-consideration of Aristotle's view that an atom is subdivisible, which was later found to be correct?

HARD
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Higher Order Thinking Skills (HOTS) Questions>Q 1
Which has more number of atoms: 100 g of potassium or 100 g of iron (Given: atomic mass of potassium =39 u, iron =56 u)?
HARD
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Higher Order Thinking Skills (HOTS) Questions>Q 2
Buckminsterfullerene is an allotrope of carbon in which atoms of carbon form pentagonal and hexagonal rings which are joined together to form a football-like round structure. Its molecular formula is C60. The molar mass of buckminsterfullerene and the number of atoms in one gram molecule of it are:
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9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Higher Order Thinking Skills (HOTS) Questions>Q 3
DDT is used as an insecticide which is banned in many countries because it causes cancer and its life-period is 10 years. Its molecular formula is C14H9Cl5. In 0.1 g of DDT,
a. how many atoms of chlorine are there?
b. how many molecules of DDT are there?
c. how many moles of DDT are there?
 
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9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Higher Order Thinking Skills (HOTS) Questions>Q 4
Cisplatin is a platinum (ll) compound used as a medicine in chemotherapy for cancer. The molecular formula of cisplatin is [Pt(NH3)2Cl2]. 0.1 g of cisplatin contains
a. how many atoms of platinum?
b. how many molecules of the compound?
c. how many moles of the compound?
 
HARD
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Higher Order Thinking Skills (HOTS) Questions>Q 5
Chloromycetin is an antibiotic used for the treatment of typhoid and eye diseases. The molecular formula of chloromycetin is C11H12N2O5Cl2. 0.2 g of chloromycetin contains
a. how many atoms of nitrogen?
b. how many molecules of the compound?
c. how many moles of the compound?
HARD
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Higher Order Thinking Skills (HOTS) Questions>Q 6
Penicillin is an antibiotic used for the treatment of infectious diseases. The molecular formula of penicillin is C16H18N2O4S. 0.2 g of penicillin contains
a. how many atoms of nitrogen?
b. how many atoms of sulphur?
c. how many molecules of the compound?
d. how many moles of the compound?
 
HARD
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>Higher Order Thinking Skills (HOTS) Questions>Q 7
Saccharin is used as an artificial sweetening agent. The molecular formula of saccharin is C7H5NO3S. 0.2 g of saccharin contains
a. how many atoms of nitrogen?
b. how many molecules of the compound?
c. how many moles of the compound?