Using the law of constant proportions which says that within the same compound, elements exist in fixed ratios.
Therefore; we can use the ratio of total mass to the mass of carbon, to determine the amount of carbon in another sample.
Mass C / Mass CH4 = Mass C / Mass CH4
43.2 g / 57.6 g = Mass C / 37.8 g
Mass C = 37.8 g × 43.2 g / 57.6 g
= 28.35 g
Hence; the percentage of carbon will be;
=(28.35/ 37.8 )× 100%
= 75 %
Thus; 75% of 37.8 g of methane is carbon
