Вычислите относительные молекулярные массы веществ, формулы которых $C_{3}H_{8}, SO_{3}, CH_{4}, NO_{2}, HBr, SF_{4}$ и $H_{2}SO_{4}$.
$M_{r}$ ($C_{3}H_{8}$) = 3 * $A_{r}$ (C) + 8 * $A_{r}$ (H) = 3 * 12 + 8 * 1 = 32.
$M_{r}$ ($SO_{3}$) = 1 * $A_{r}$ (S) + 3 * $A_{r}$ (O) = 1 * 32 + 3 * 16 = 80.
$M_{r}$ ($CH_{4}$) = 1 * $A_{r}$ (C) + 4 * $A_{r}$ (H) = 1 * 12 + 4 * 1 = 16.
$M_{r}$ ($NO_{2}$) = 1 * $A_{r}$ (N) + 2 * $A_{r}$ (O) = 1 * 14 + 2 * 16 = 46.
$M_{r}$ ($HBr$) = 1 * $A_{r}$ (H) + 1 * $A_{r}$ (Br) = 1 * 1 + 1 * 80 = 81.
$M_{r}$ ($SF_{4}$) = 1 * $A_{r}$ (S) + 4 * $A_{r}$ (F) = 1 * 32 + 4 * 19 = 108.
$M_{r}$ ($H_{2}SO_{4}$) = 2 * $A_{r}$ (H) + 1 * $A_{r}$ (S) + 4 * $A_{r}$ (O) = 2 * 1 + 1 * 32 + 4 * 16 = 98.