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#### Atoms and Molecules Book Back Questions

10th Standard EM

Reg.No. :
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Science

Time : 00:45:00 Hrs
Total Marks : 30
4 x 1 = 4
1. Th e volume occupied by 4.4 g of CO2 at S.T.P

(a)

22.4 litre

(b)

2.24 litre

(c)

0.24 litre

(d)

0.1 litre

2. The volume occupied by 1 mole of a diatomic gas at S.T.P is

(a)

11.2 litre

(b)

5.6 litre

(c)

22.4 litre

(d)

44.8 litre

3. The gram molecular mass of oxygen molecule is

(a)

16 g

(b)

18 g

(c)

32 g

(d)

17 g

4. 1 mole of any substance contains __________ molecules

(a)

6.023 × 1023

(b)

6.023 × 1023

(c)

3.0115 × 1023

(d)

12.046 × 1023

5. 5 x 1 = 5
6. The sum of the numbers of protons and neutrons of an atom is called its __________

()

mass number

7. The average atomic mass of hydrogen is ___________ amu.

()

1.0079

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

()

atomicity

9. One mole of any gas occupies ________ ml at S.T.P

()

22400

10. Atomicity of phosphorous is ___________

()

4

11. 3 x 2 = 6
12. Define : Relative atomic mass.

13. Define : Atomicity

14. Find the percentage of nitrogen in ammonia.

15. 2 x 4 = 8
16. Calculate the number of water molecule present in one drop of water which weighs 0.18 g.

17. Give the salient features of “Modern atomic theory”

18. 1 x 7 = 7
19. Calculation of molar mass
Calculate the gram molar mass of the following.
1) H2O
2) CO2
3) Ca3 (PO4)2