Question

calculate the number of molecules of water in 1.8 c. c. water at 4 degree Celsius ​

Answer 1

Given:

Volume of water = 1.8 cc at 4°C .

To find:

Number of water molecules

Calculation:

Density of water at 4°C = 1 g/cc ;

Let mass of water be m:

$\rm{m = volume \times \rho}$

$= > \rm{m = 1.8 \times 1}$

$= > \rm{m = 1.8 \: gm}$

Moles of water

$\rm{ = \dfrac{given \: mass}{molar \: mass} }$

$\rm{ = \dfrac{1.8}{18} }$

$\rm{ = 0.1 \: mole}$

Hence, total number of molecules

$\rm{ = moles \times avagadro \: no.}$

$\rm{ = 0.1 \times 6.0223 \times {10}^{23} }$

$\rm{ = 6.0223 \times {10}^{22} \: molecules}$

So, final answer is:

$\boxed{ \sf{ total \: molecules = 6.0223 \times {10}^{22} \:}}$