Question

BASED ON THE INFORMATION BELOW. CALCULATE THE MASS FOR ONE OF THESE ATOMS:

Answer 1

C = 12 g

O = 16 g

H = 1 g

Further explanation

Conservation of mass stated that  

In a closed system, the masses before and after the reaction are the same

we can calculate the mass of each atom in the compound :

O in O₂ :

mass O₂ = 32

mass O = 32 : 2 = 16 g

H in H₂O

mass H₂O = 18

mass 2.H + mass O = 18

mass 2.H + 16 = 18

mass 2.H=2

mass H = 1 g

C in CH₄

mass CH₄ = 16

mass C + mass 4.H = 16

mass C + 4.1=16

mass C = 12 g

or we can use formula :

Mass of a single C :

$\tt =\dfrac{Ar~C}{MW~CO_2}\times mass~CO_2\\\\=\dfrac{12}{44}\times 44=12$