A carboxylic acid $X$ is treated with ammonia. Product $Y$ is isolated and heated to obtain a compound $Z$ of molecular formula $C_3H_7ON$.
1) Write the condensed formulas of $X$, $Y$ and $Z$
2) There was obtained $14.6\;g$ of $Z$ with a yield of $85\%$.
What was the mass of $Y$ on start?
1)
$Z$: $CH_3CH_2CONH_2$ propanamide
$Y$: $CH_3CH_2COO^-NH_4^+$ ammonium propanoate
$X$: $CH_3CH_2COOH$ propanoic acid
2)
If the yield was $100\%$, one would have obtained $14,6\cdot \frac{100}{85}$ $=$ $17,2\; g$ $Z$
$n_{Z}$ $=$ $\frac{17.2}{3\cdot 12+7\cdot 1 +16+14}$ $=$ $0.235\; mol$
Dehydration of the ammonium salt:
$C_3H_9O_2N$ $\rightarrow$ $C_3H_7ON$ $+$ $H_2O$
$n_{salt}$ $=$ $n_{Z}$ $=$ $0.235$
$M_{salt}$ $=$ $0.235\cdot 92$ $=$ $21.4\; g$
