a 0.286 - g sample of gas occupies 125 ml at 60. cm of hg and 25°c. what is the molar mass of the gas?\n59…
a 0.286 - g sample of gas occupies 125 ml at 60. cm of hg and 25°c. what is the molar mass of the gas?\n59 g/mol\n5.9 g/mol\n44 g/mol\n71 g/mol
Answer
Explanation:
Step1: Convert units
$P = 60\ cm\ Hg=\frac{60}{76}\ atm$, $V = 125\ mL = 0.125\ L$, $T=25 + 273 = 298\ K$, $m = 0.286\ g$
Step2: Use ideal - gas law $PV=nRT$ to find $n$
$n=\frac{PV}{RT}=\frac{\frac{60}{76}\ atm\times0.125\ L}{0.0821\ L\cdot atm/(mol\cdot K)\times298\ K}$
Step3: Calculate molar mass $M$
$M=\frac{m}{n}=\frac{0.286\ g}{n}\approx44\ g/mol$
Answer:
C. 44 g/mol