How many representative particles are in 6.8 g of #H_2O#?

1 Answer
Feb 4, 2017

#"Number of particles"# #-=# #"Mass"/"Molar mass"xxN_A#, where #N_A="Avogadro's number", 6.022xx10^23#.

Explanation:

I KNOW that an #18.01*g# mass of water contains #"Avogadro's number of molecules"#, i.e. #6.022xx10^23# INDIVIDUAL WATER molecules.

And thus the number of water molecules, i.e. representative particles, in a #6.8*g# mass is:

#(6.8*g)/(18.01*g*mol^-1)xx6.022xx10^23*mol^-1-="How many water molecules"#.