Question

find the number of moles present in 20 grams of NaOH​

Answer 1

Answer:

Number of moles which make up 20 grams of NaOH = (20 grams × 1 Mole)/(40 grams) = 0.5 moles.

Answer 2

Answer:

Weight of NaOH(w) = 20g

Molar mass of NaOH(m) = 40g/mol

No. of moles(n) = w/m

n = 20/40

n = 0.5

no. of molecules in 1 mol = 6.022 ×10²³

no. of molecules in 0.5 mol = 0.5×6.022×10²³

no. of molecules in NaOH = 3.011×10²³ (answer)

The number of molecules in 20g NaOH is 3.011 x 10^23. First find out the molecular mass of NaOH which is 40g(Na = 23, O=16, H=1). Now find out the number of moles i.e. given mass/molecular mass (given mass is 20 g) so the number of moles will be 20/40 which equals 1/2 i.e 0.5 moles. Now multiply 0.5 by the Avogadro's number i.e 6.022 x 10^23 and you will get the answer

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