Question

the number of moles present in 69gm of sodium

Answer 1

molar mass = 23

no. of moles = given mass / molar mass

= 69/23 =3moles

Answer 2

Given :-

69 gm of sodium ( Na)

Question :- To calculate no.of moles.

Formula to be used :-

No of moles = m /M

where " m " is mass and " M " is Molar mass .

Calculating molar mass :-

1 mole of Na .

» Mostly for all the elements except a few molar mass will be double of its atomic number

» Na ( sodium) is also one of the exception.

→ it's molar mass = 23

Na - atomic number :- 11 , double of it 22 but we take 23 .

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n = m / M

n = 69/23

n = 3

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Answer :- 3 moles

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Glad if helped.