Question

The volume of a drop of water is 0.04 ml. How many H20 molecules are there in a drop of water?​

Answer 1

Answer:0.04/22.4*6.022*10^23

Explanation:

1mole =volume given/22.4ltr at ntp or stp

Mole*6.022*10^23=no of molecule

Answer 2

Answer:

There are $1.3384 * 10^{21}$ molecules present in a drop of water.

Explanation:

Mass of 1 drop of water = volume x density

We know that the density of water is 1.0g/mol. Therefore,

Mass of 1 drop of water = 0.04ml × 1.0g/mol

Mass of 1 drop of water = 0.04g

Molecular mass of $H_2O$ = 2 x 1 + 16 = 18g

One mole $H_2O$ weighs 18 g and contains $6.023 * 10^23$ $H_2O$ molecules.

Number of $H_2O$ molecules in 0.04g of water

$=\frac{6.023*10^{23}*0.04}{18}$

$=\frac{0.24092*10^{23}}{18}$

$=1.3384*10^{21}$

Therefore, there are 1.3384 × 10^21 molecules in a drop of water.

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