What mass of nitrogen, N2, will contain the same number of molecules as 1.8 g of water, H2O? (Atomic masses: N = 14 u; H = 1 u; O = 16 u)
Given mass of water = 1.8g
Molar mass of water = 18g
No. of moles of water = given mass of the element/ molar mass of the element = 1.8g/18g = 0.1 moles
Equal number of moles of all the substances contain equal number of molecules.
So, 0.1 moles of water and 0.1 moles of nitrogen contains same no. of molecules.
Hence, mass of 0.1 mole of nitrogen = 0.1 × 28 g = 2.8 g.