Question

# The density of the water at room temperature is ( 1.0 mathrm{g} / mathrm{mL} . ) How many molecules are there in a drop of water if its volume is ( 0.05 mathrm{mL} ) ?

Solution

( P=frac{M}{V} )

(M=P cdot V )

( M=0.05 times 1=0.05 mathrm{g} )

( begin{aligned} n_{text {mskentes }}=& frac{M}{M} times A =& frac{0.05}{18} times 6.022 times 10^{23} =& 1.67 times 10^{21} text { Molecules } end{aligned} )