Question

A sample of ethane has the same mass as 10.0 million molecules of methane. How many C2H6 molecules does the sample contain? Please solve fastt

Answer 1

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$\implies$ As, we know Molar mass of methane = 16gm/mol

$\implies$ Given Mass of given sample of C2H6 = mass of 107 methane molecules

$\implies$ 1 Avagadro constant = 6.022 × 10^23 particles

$\implies$ = 16 × 107/Avagadro constant

$\implies$No. of C2H6 molecules

$\implies$= Mass / 30 × Avagadro constant

$\implies$= (16 × 107/Av. const × 30) × Avagadro constant

$\implies$= 5.34 × 106.

Answer 2

Hey dude ,

Molar mass of methane = 16 g/mol

1 mole of methane contains = 6.023 x 1023 molecules

Mass of 6.023 x 1023 molecules of methane = 16 g

​Mass of 1 molecule of methane = 16/ (6.023 x 1023 ) g

Mass of 10 million molecules or 10 x 106 molecules = [​16/ (6.023 x 1023 ) ] x 107 = 2.65 x 10-16 g

Thus mass of ethane sample = ​ 2.65 x 10-16 g

​Molar mass of ethane or mass of 1 mole of ethane = 30 g/mol

If 30 g of ethane contain = 6.023 x 1023 molecules

Then ,

​ 2.65 x 10-16 g of ethane contains = [6.023 x 1023 /30] x 2.65 x 10-16 = 5.3203 x 106 molecules of ethane