Question

The number of water molecules present in a drop of water (volume 0.0018 ml) at room temperature is
A.1.568 x 103
B.6.023 x 1019
C.4.84 x 1017
D.6.023 x 1023

Answer 1

ĀNSWĒR ⏬⏬

B. 6.023×1019


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Density of water = 1.

So 1 = mass/volume, 1 = mass/0.0018, mass = 0.0018g no. of mole = weight/molecular

weight = 0.0018/18.

No of water molecules = No of mole*Avogadros no.

= 0.0018/18*6.023*10exp23 = 6.023*10exp19

THANKS ✌✌✌

Answer 2

Hello,

Density of water = 1 g/ml

Mass of 0.0018 ml of water = 0.0018×1 = 0.0018 g

Molar mass of water = 18 g/mol

Number of moles in 0.0018g of water = 0.0018/18 = 10^-4 mole

Number of water molecules in 1 mole = 6.022×10^23 molecules

Number of water molecules in 10^-4 mole

= 10^-4 × 6.022 × 10^23

= 6.022 × 10^19 molecules

Therefore,

Correct option B)

Thank you!