in chemistry he have to study atoms,molecules,etc.as u know these all are very small in their size.it is very hard to mesure the mass of a singal atom so scientist developed a new system that we call mole system.
1 mole = 6.022 * 10^23.it is like 1 dozen = 12,1 grros =144
2).11.1 MOLE of O2 is required.
3).69 g of O2 is used
4).239.14 g of CO2 & 146.73 g of H2O is made.
