Which of the following contains same number of carbon atoms as are in 6.0g of carbon ( C-12) ?

Options

A. 6.0g ethane
B. 8.0g methane
C. 21.0g Propane
D. 28.0g CO

Answer

b

Explanation

6g of carbon `= ( 6)/( 12) = 0.5` mol.
The given choice should contain 0.5 mol of carbon atoms.
6g of ethane `( C_(2) H_(6)) = ( 6)/( 30) = 0.2 `mol
( a) 1 mol of ethane = 2 mol of carbon atoms
0.2 mol `= 2 xx 0.2 xx 6.023 xx 10^(23)` carbon atoms
`= 0.4 xx 6.023 xx 10^(23)` carbon atoms
( b) 1 mole of methane = 1 mol of carbon atom
8g of methane = `( 8)/( 16) = 0.5 `mol
`:.` 0.5 mol of methane = 0.5 mol of carbon atom
( c ) 21 g of propane `= ( 21)/( 44) = 0.477` mol.
1 mol of `C_(3) H_(8) = 3` mol of carbon atoms
0.477 mol of `C_(3) H_(8) = 3 xx.477 = 1.432 ` mol of carbon atom
( d) 28g of CO = 1 mol = 1 mol of CO.
Hence 6g of carbon and 8g of methane contain same number of carbon atoms.