Question

calculate the no. of molecules in 1.5l of water at s.t.p​

Answer 1

1500 moles of molecules are contained in 1.5 l of water

Answer 2

$\large{noofmoles=givenmass/molarmass}$

$\large{givenmasofh2o=1.5litre=1.5X1000}$

$\large{H2O=1500g}$

$\large{molarmassofH2O=1+1X2+8+8}$

$\large{molarmassofH2O=20u}$

$no \: of \: moles = \frac{1500g}{20u} = 75mol$