Question

in 90g of water how many molecules are present in it​

Answer 1

Explanation:

To determine the number of molecules in a particular compound, we need to first determine the number of moles present in that mass.

18 g of H2O =1 mole

1 g of H2O=(1÷18) moles

90 g of H2O= (1÷18)×90 moles=5 mole0

Now, as we know,

1 mole=6.022×10^(23) molecules

therefore 5 moles= 5×6.022×10^(23)=30.11 ×10^(23) molecules

Hence 90 g of water will contain 30.11×10^(23) molecules.

Answer 2

Answer:

5 NA=5(6.022×10^23)

Explanation:

no.of molecules = mole × NA

mole= given mass / molecular mass

mole= 90/18

mole= 5

no. of molecules= 5 NA.

where NA = 6.022×10^23

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