CBSE - Atoms and Molecules

1 Atoms and Molecules 

The chemical formula of Plaster of Paris is

(1) Calcium Sulphate [CaSO₄]
(2) Calcium Sulphate Hemihydrate [CaSO ½H₂O]
(3) Barium Sulphate [BaSO₄]
(4) None of these
 

2 Atoms and Molecules 

The number of atoms constituting a molecule is known as ........

(1) valency
(2) atomicity
(3) mole concept
(4) atomic mass

3 Atoms and Molecules 

You have the mythical metal element 'X' that can exhibit variable valences 1, 2 and 5. Which of the following is/are not the correct chemical formula/formulae for the compounds formed by the combination of the "X" ions with different radicals ?

(A) XPO₄ (B) X₂SO₄ (C) X₅ClO₄ (D) X₃NO₃

(1) Only B
(2) B and C
(3) A, C and D
(4) B and D 

4 Atoms and Molecules 

You are provided wit h 64 g of sulphur in cont ainer A and 64 g of O₂  in container B. Which will have more number of molecules ? (Atomic mass of S=32, O=16)

(1) 64 g of S
(2) 64 g of O₂
(3) both have equal number of molecules
(4) cannot calculate with the given information.

5 Atoms and Molecules 

Which of the following contains maximum number of molecules? 

(1) 1g N₂
(2) 1g CO₂
(3) 1g H₂
(4) 1g O₂

6 Atoms and Molecules 

The number of atoms in 0.1 mole of Sodium (Na) is

(1) 6.022 × 10²³
(2) 6.022 × 10²²
(3) 6.022 × 10²¹
(4) 6.022 × 10²⁴

7 Atoms and Molecules 

The pH value of a solution prepared by dissolving 4g NaOH in 100 litre of water is

(1) 13
(2) 14
(3) 12
(4) 11

8 Atoms and Molecules 

Which one of the following is the smallest in size ?
(1) N^3–
(2) O^2–
(3) F^–1
(4) Na⁺

9 Atoms and Molecules 

Which of the following is an element ?

(1) Mercury
(2) Ammonia
(3) Water
(4) Glucose

10 Atoms and Molecules 

Molecular formula of baking soda is .....

(1) Na₂CO₃
(2) NaCl
(3) NaHCO₃
(4) NaOH