Question

what is the mole concept calculate the number of molecules in 45g of water

Answer 1

mole is a simple method to meaure no. of things just like dozen implies 12, pair implies 2
and so on. In same way 1 mole implies 6.023×10^23
18 gm water is 1 mole of water
45 gm water implies 45/18 moles of water
1mole contain 6.023×10^23 molecules
so 45/18 mole contain 45/18×6.023×10^23