Mole Concept Multiple Choice Questions and Answers for Practice

16. Atomic mass of an elements is

1. the actual mass of one atom of the element
2. the relative mass of an atom of the element
3. the average relative mass of different atoms of the element
4. much different from the mass number of the element.

17. Avogadros number represents the number of atoms in

1. 12g of C¹²
2. 320g of sulphur
3. 32g of oxygen
4. 12.7g of iodine

18. How many grams are contained in 1 gram-atom of Na?

1. 13g
2. 23g
3. 1 g
4. 1/23g

19. I mole of a compuund contain 1 mole of C and 2 moles of O. The molecular weight of the compound is

1. 3
2. 12
3. 32
4. 44

20. Mass of a mole of electrons is

1. 0.20mg
2. 0.02mg
3. 0.55mg
4. 1.00mg

21. Number of atoms of oxygen present in 10.6g Na₂Co₃ will be

1. 6.02 × 10²²
2. 12.04 × 10²²
3. 1.806 × 10²³
4. 31.80 × 10²³

22. Number of electrons in 1.8 mL of H₂O is

1. 6.02 x 10²³
2. 3.011 x 10²³
3. 0.6022 x 10²³
4. 60.22 x 10²³

23. Number of water molecules in the drop of water,if 1 ml of water has 20 drops and A is Avogadros number, is

1. 0.5A/18
2. 0.05A (C)0.5A
3. 0.05A/18

24. One mole of oxygen gas is the volume of

1. 1 litre of oxygen at S.T.P.
2. 32 litres of oxygen at S.T.P.
3. 22.4 litres of oxygen at S.T.P.
4. 6.02 × 10²³ molecules of oxygen at any temperature and pressure.

25. The mass of carbon present in 0.5 mole of K₄ [Fe(CN)₆] is

1. 1.8 g
2. 18 g
3. 3.6 g
4. 36 g

26. The maximum no. of molecules is present in

1. 15 L of H₂ gas at S.T.P
2. 5 L of N₂ gas at S.T.P
3. 0.5 g of H₂ gas
4. 10 g of O₂ gas

27. The number of g-atom of oxygen in 6.02 × 10²⁴ CO molecules is

1. 1
2. 0.5
3. 5
4. 10

28. The number of moles of carbon dioxide which contain 8 g of oxygen is

1. 0.5 mol
2. 0.20 mol
3. 0.40 mol
4. 0.25 mol

29. The total no of ions present in 111 g of cacl₂ is

1. One mole
2. Two mole
3. Three mole
4. Four moles

30. The weight of 350 mL of diatomic gas at 0 degree Centigrate and 2 atm pressure is 1g. The wt. of one atom is

1. 16/N
2. 32/N
3. 16 N
4. 32 N (N is the Av. const.)