Question

A sample of ethane (C2H6)has the same mass as 1.5 into 10^20 molecules of methane (CH4).How many molecules does the sample contain?​

Answer 1

Answer:

0.8x10^20

Explanation:

If molar masses are ; C = 12.0 g/mol , H = 1.0 g /mol

molar mass of CH4 = 16 g/mol

as N=nL (which is , N = number of molecules , n = number of molecules in moles , L = Avogadro constant = 6.022 x 10^23)

and n=m/M (Where n is the same , M = molar mass , m = total mass )

then ,

m=NM/L=1.5x10^20x16g/mol / 6.022x10^23 /mol

  =3.985x10^-3g = 3.985mg (mass of 1.5x10^20 molecules of methane)

N of ethane = ?

M C2H6 = 30g/mol

N=mL/M = 3.985x10^-3g x 6.022x10^23/mol /30g/mol

  =0.8 x 10^20