PRACTICE QUESTIONS SET- 1 1. The relative abundance of various isotopes of silicon is as Si(28)=92.25%, Si(29)=4.65%and Si(30)=3.10%.Calculate the average atomic mass of silicon?
2. Calculate the number of atoms in each of the following i)52 moles of argon ii)52 u of He iii) 52g of He
3. Calculate the mass of 6.022 × 1023 molecule of Calcium carbonate (CaCO3).
4. Calculate the mass of 12.044 × 1023 carbon atoms.
5. Calculate the number of oxygen atoms in 1 mole of O2.
6. Calculate the number of moles, and number of atoms of H,
S, and O in 5 mole of H2SO4.
7. Calculate the number of oxygen atoms and its mass in 50 g
of CaCO3.
8. Calculate the number of atoms of each element in 122.5 g
of KClO3
9. What is the molar mass of (a)silver nitrate(AgNO3)
(b) Carbon dioxide (CO2) (c) sulphuric acid (H2SO4) (d) hydrogen chloride(HCl)
(e) zinc chloride(ZnCl2)
10. How many molecules of water are there in 54 g of H2O ?
11. How many atoms of hydrogen are there in 36 g of NH3?