Question

calculate the no. of atoms in (a) 5L of o2 gas at stp (b) 4.4 g of CO2 (c) 52 u of He​

Answer 1

22.4 L of O2 contains Avogadro no. of molecules, so 5 L of O2 contains 5 × Avogadro no. then divide it by 22.4 , now these are molecules , since one O2 molecule contains 2 atoms , so multiply the above by 2 .

44 g of CO2 contains Avogadro molecules , so 4.4 g contains Avogadro/10 molecules , & one molecule contains 3 atoms so total atoms is 3× Avogadro/10

mass of one he atom is 4u , so 52 u contains 13 atoms of he