Atomic Mass and Molecular Mass



1. State Avogadro’s Hypothesis.
2. Explain why atomic weights of elements are not whole number.
3. State Avogadro’s Hypothesis. Show that molecular weight = 2 × vapour density.
(5 marks)
4. How heavy is one atom of hydrogen?
5. What weight of 60% pure sulphuric acid is required to decompose 25gm of chalk
(CaCO3)?
6. Calculate the mass of two atom of nitrogen.
7. Calculate the mass of one molecule of Hydrogen.
8. An oxide of trivalent metal contains 32% of oxygen. Calculate the atomic mass of the metal.
9. An oxide of nitrogen contains its half-volume of nitrogen and its vapour density is
15. Determine its molecular formula.
10. One-volume of hydrogen reacts with one-volume of chlorine to give two-volume
hydrogen chloride gas. Which law of stoichiometry is illustrated? State the law.
11. One atom of an element ‘A’ weights 6.644 × 110-23g. Calculate the number of gram atom in 80 kg of its.
12. Calculate the mass of 120cc of nitrogen at NTP. How many numbers of molecules are present in it?
13. Which of the following has larger number of molecules and how? 7 grain of nitrogen or 1 grain of hydrogen.
14. What weight of Na will contain the same number of atoms as are present in 1.2gm of Carbon (C12)?
15. How many gram atoms of sulphur and how many gram of oxygen are needed to prepare 6.023 × 1024, molecules of SO2?
16. State and explain Avogadro’s hypothesis. How this theory can be used to determine the molecular weight of gas? (5 marks) 

Have a question? Ask us in our discussion forum.