Chemistry Class 9 Chapter 1 Think-Thank, Federal board
Think-Thank Chapter 1 Fundamentals of chemistry 1. What mass of sodium metal contains same number of atoms as 12.00 g of carbon. Ans. 12.00g of carbon = 1 mole of carbon No. of atoms in 1 mole of C = N A = 6.022 x 10 23 1 mole of Na = 23 g So, no. of atoms in 1 mole of Na = N A = 6.022 x 10 23 Hence, 23g of Na contains same number of atoms as 12g of C. 2. What mass of oxygen contains same number of molecules as 42g of nitrogen. Ans. Molar mass of N 2 = 2 x 14 = 28g 28g of N 2 = 1 mole 1g of N 2 = 1 / 28 mole 42g of N 2 = (1/28) x 42 = 1.5 mole No. of molecules = 1.5 x 6.022 x 10 23 ...
