Question

pls help me tomorrow is my exam and I'm unable to understand it

Answer 1

HEYA!

One drop of water has the weight = 0.05 g.  

 

The molar mass of water (H2O) is 18.0 grams/mol (1.008 + 1.008 + 16.0).

 

This means there is one mole of water in 18.0 grams. One mole is 6.02 × 10^23 molecules.

Then the number of atoms in 0.5 g:

0.05 grams ÷ 18.0 grams × (6.02 × 10^23 molecules)= 1.67 × 10^22 molecules

HOPE YOUR DOUBT IS CLARIFIED

:)

BEST OF LUCK FOR UR EXAMS

WITH WARM REGARDS

@SEASONIND

 

Answer 2

We know that : 1 Mole of Water Molecules weigh 18 grams

We know that : 6.023 × 10²³ Molecules make up a Mole

⇒ 18 grams of Water contains 6.023 × 10²³ Molecules

⇒ 0.05 gram of Water contains :  $\dfrac{[(6.023 \times 10^2^3) \times 0.05]}{18}$

⇒ 0.05 gram of Water contains : 1.673 × 10²¹ Molecules of Water