how many molecules of water are present in 1ml of water?

The molar mass of water is 18g and its density is 1g/ml. Therefore, if we calculate the mass of water present in 1 ml of water and then divide it by 18 (molar mass of water), we will get the number of molecules of water present in one gram of water. 

So as density = mass / volume

Therefore, mass of 1 ml of water = density X volume

= 1 X 1 = 1g

Now, the molar mass of water is 18g. This means that there are 6.023 X 10²³ molecules of water present in 18g of water. Therefore 

 18g of water = 6.023 X 10²³ molecules of water

 So 1g of water = (6.023 X 10²³ / 18) molecules of water

 = 3.346X 10²² molecules of water

 Thus there are 3.346X 10²² molecules of water present in 1 ml of water.