Which of the following have the same percentage of carbon by mass? — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

$C_2H_6$ and $CH_3-CH_3$ are the same compound (ethane). All other pairs ($CH_4, C_2H_6, C_3H_8$) have different $C:H$ ratios and thus different mass percentages.