How many atoms of c are there in 25 grams of c5h12 ? (pentane)

Molar mass C5H12 = 12 x 5 + 1 x 12 => 72 u

number of moles = 25 / 72 => 0.3472 moles

C => 5 atoms ( 0.3472 x 5 ) => 1.736 moles C

1 mole 6.02 x 10²³ atoms
1.736 moles ( atoms C )

atoms C = 1.736 x ( 6.02 x 10²³ ) / 1

= 1.04 x 10²⁴ atoms of C

hope this helps!

Molar mass pentane = 12 x 5 + 1 x 12 => 72 u

No. of moles = 25 / 72 => 0.3472 moles

Carbon
 5 atoms ( 0.3472 x 5 ) => 1.736 moles C

1 mole 6.02 x 10²³ atoms
1.736 moles ( atoms C )

No. of atoms of Carbon = 1.736 x ( 6.02 x 10²³ ) / 1

No. of atoms of Carbon = 1.04 x 10^24 atoms of Carbon

Its the second one nonmetals are moldable and easily shaped