NTSE MCQs 2 on "ATOMS AND MOLECULES"

These are MCQs 2 of "ATOMS AND MOLECULES" . Practice MCQs to check your knowledge for Entrance examination like NTSE etc.

1. Arrange the following in increasing number of molecules: i. 0.5 moles of H₂ ii. 4 g of H₂ iii. 18 g of H₂O iv. 2.2 g of CO₂

• I < iii < iv < ii
• Iv < i < iii
• I < ii < iii < iv
• Iv < iii < ii < i

2. Out of 1 g of oxygen gas, 1 g of oxygen atoms and 1g of ozone , maximum number of atoms are present in:

• 1g of oxygen gas
• 1g of oxygen atoms
• 1 g of ozone
• All have equal number of atoms

3. The number of atoms present in 0.5 moles of Nitrogen atoms is same as in:

• 12 g of C
• 24 g of Mg
• 8 g of O
• 32 g of S

4. Which of the following is not a postulate of Dalton’s atomic theory:

• All matter is made up of atoms
• Atoms are tiny indivisible and indestructive ultimate particles
• Atoms combine in small whole number ratios to form compounds
• Atoms of different elements can have the same mass

5. 16g of S₈ contains:

• 6.023 x 10²³ Atoms of S
• 6.023 x 10²³/8 atoms of s
• 6.023 x 10²³/2 atoms of S
• 6.023x10²³/16 atoms of S

6. Which of the following has the smallest number of molecules?

• 0.1 moles of CO₂
• 2 g of H₂ at STP
• 16 g of O₂ gas
• 3.4 g of NH₃

7. An element X has valency equal to 3. What will be its formula with carbonate ions?

• X₂CO₃
• XCO₃
• X₂(CO₃)₃
• X(CO₃)₃

8. The mass of a single atom of an element X is 2.65X 10^-23g. The atomic mass and name of the element is:

• 16u, oxygen
• 16u, Sulphur
• 32u, oxygen
• 32u, Sulphur

9 a. Oxygen: diatomic
b. Ozone :_______?

• Monoatomic
• Diatomic
• Triatomic
• Tetra atomic

10. a. 24g of Mg: 1 mole
b. 35.5g of Cl₂: _________

• 0.5 mol
• 1 mol
• 2 moles
• 2.5 moles