MCQ ATOMIC STRUCTURE CLASS IX [1]

1. All sample of carbon dioxide contains carbon and oxygen in the mass ratio of 3:8.This is in agreement of law of

(a)conservation of mass                   (b) constant proportions

(c) multiple  proportion                     (d) gaseous volume

2. The indivisibility  of atom was proposed by

(a) Rutherford                                     (b) Dalton

(c) Bohr                                                (d) Einstein

3. The value of the Avogadro constant  is

(a) 6.022 x 10^{– 22}                   (b) 6.022 x 10^{– 24}

(c) 6.022 x 10 ^{– 23}                  (d) None of these 

4. The volume of 1 mole of gas at standard temperature and pressure is

(a) 11.2 litres                                        (b) 22.4litres

(c) 100 litres                                         (d) none of these

5. The atomic mass of sodium is 23. The number of moles in 46 g of sodium is

(1) 1                                                      (b) 2       

(c) 2.3                                                   (d) 4.6

6. Empirical formula of a compound of molecular mass 120 is CH₂O. The molecular formula of the compound is

(a) CH₄0₂                                              (b) C₄H₈0₄

(c)C₃H₆ O₃                                            (d) none of these

7. Which of the following is a tetra atomic molecule.

(a) O₂                                                    (b) O₃     

(c) NO₂                                                 (d) SO₃

8. The number of atoms present in a molecule of a substance is called

(a) molecularity                                   (b) atomicity

(l)  valency                                          (d) reactivity

9. The valency of nitrogen in ammonia (NH₃) is

(a)  2                                                     (b)  0      

(c)  3                                                     (d)  4

10. The molecular formula of ethanoic acid is C₂H₄O₂ . Its empirical formula is

(a) C₄H₈O₂                                            (b) CH₂O

(c) CHO                                                (d) CHO₂

Answers.

1	b	6	b
2	b	7	b
3	c	8	b
4	b	9	c
5	b	10	b