Question

Calculate the number of molecules in a drop of water weighing 0.05g . Also find the number of H- atoms and O- atoms present in same amount.​

Answer 1

first of all we need to calculate the number of moles of water molecules

i.e 0.05g of h2o

moleular weight of water is 18 g

number of moles = weight/grammolecularweight

=0.05/18

=0.0027.

number of molecules= no. of moles*avagadronumber

=0.0027*6.023*10^23

0.016*10^23

number of atoms in water molecule=3

0.016*3*10^23

=0.0487*10^23.

Hope it's Helpful for you....

Answer 2

Molecular mass of water = 18 g

No. of moles in 0.05 g of water = 0.05/18

= 2.78 x 10-3 mol

One mole = 6.023 x 1023 molecules

Therefore, 2.78 x 10-3 mol of water contain = 2.78 x 10-3 6.023 x 1023 molecules

= 1.67 x 1021 molecules