Question

Calculate the no of water molecules in a drop of volume 0.05ml

Answer 1

Answer:

1 mole of water =18g

Explanation:

That means it contains 0.01 moles of water molecules, or 6 x molecules. 1 drop is roughly equal to 1/20 ml = 0.05 ml. 1 mole of water weighs 18 g.

Answer 2

Answer:

$1.67 * 10^{21}$

Explanation:

We know that 1ml = 1g ∴ 0.05ml = 0.05g

Moles = Given weight/Molecular Weight

Molecular Weight of $H_{2} O$ is 18

⇒ Moles = $\frac{5}{18*10^{2} }$

We also know that Moles = Given no. of Particles/6*$10^{23}$

⇒ Given no. of Particles = Moles * $6*10^{23}$

⇒x = $\frac{5}{18*10^{2} }$ * $6*10^{23}$

    = $1.67 * 10^{21}$ = Ans