Question

Mass of the sample which is having 3.01 x 10^23 molecules of water will be -
(1) 9 gm
(2) 6 gm
(3) 18 gm
(4) none of these​

Answer 1

Answer:

Number of molecules of water= 3.01*10^23

We know that

18 g of water =6.022*10^23molecules

So,

1 molecule of water =18/6.022*10^23

3.01*10^23 molecules =18/6.022*10^23*3.01*10^23

=9gm

Answer 2

Answer:

(1) 9 gm

Explanation:

Mass of H20= 9*10^-3

Concept- Formula used for that is as follows -

Number of molecules=variety of moles x Avogadro variety

N=n x A

Where, N= Number of molecules

n= variety of moles

A= avogadro variety

Number of moles= Mass of substance/ molar mass

Given-

Number of molecules of H2O= 3.01x10^20

Molar mass of water= 18

Find - Mass of the H20 molecules

Step through step explanation -

Number of molecules=variety of moles x Avogadro variety

3.01x10^20= n x 6.02*10^23

n = 3.01x10^20/6.02*10^23

n=0.5x10^-3

variety of moles= 0.5x10^-3

variety of moles-Mass of substance/ molar mass

0.5*10^-3= mass of H20/18

mass of H20= 0.5*10^-3*18

mass of H20= 9*10^-3

So, the answer is (1) 9 gm

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