$33.6 \mathrm{cc}$ of phosphorus vapour weighs $0.0625 \mathrm{g}$ at $546°\mathrm{C}$ and $76 \mathrm{cm} \mathrm{Hg}$ pressure. What is the molecular weight of phosphorous? How many atoms are there in one molecule of phosphorus vapour?

In a Victor Meyer determination, $0.0926 \mathrm{g}$ of a liquid gives $28.9 \mathrm{mL}$ of gas, which is collected over water and measured at $16°\mathrm{C}$ and $753.6 \mathrm{mmHg}$ pressure. Calculate molecular weight and vapour density of the substance. (Aqueous tension at $16°\mathrm{C}=13.6 \mathrm{mmHg}$.)

A Dumas bulb of capacity $200 \mathrm{mL}$ weighs $22.567 \mathrm{g}$ at $120°\mathrm{C}$. When it is filled with vapours of a substance at $120°\mathrm{C}$ and $755 \mathrm{mm} \mathrm{Hg}$ pressure, it weighs $22.8617 \mathrm{g}$. Find the molecular weight of the substance.

$0^{°}\mathrm{C}=273 \mathrm{K} \mathrm{and} \mathrm{R}=0.082 \mathrm{atm} \mathrm{L} {\mathrm{mol}}^{-1}{\mathrm{K}}^{-1}$

give the answer up to one place of decimal.

$0.2704 \mathrm{g}$ of a substance when introduced into a Hofmann tube, generated $110 \mathrm{mL}$ of vapours at $99.6°\mathrm{C}$ and $747 \mathrm{mm} \mathrm{Hg}$ pressure. The height of mercury inside the tube was found to be $285.2 \mathrm{mm}$. Calculate the molecular weight of the substance. 

Report your answer up to four significant figures.