650 mm Hg es lo mismo que 650 torr y equivalen a :
<img src="https://tex.z-dn.net/?f=650%5C%20mm%5CHg%5Ccdot%20%5Cfrac%7B1%5C%20atm%7D%7B760%5C%20mm%5C%20Hg%7D%20%3D%200%2C86%5C%20atm" />
Aplicando la ley de Boyle - Mariotte : <img src="https://tex.z-dn.net/?f=P_1%5Ccdot%20V_1%20%3D%20P_2%5Ccdot%20V_2" />
a) <img src="https://tex.z-dn.net/?f=V_2%20%3D%20%5Cfrac%7B0%2C86%5C%20atm%5Ccdot%20800%5C%20mL%7D%7B1%5C%20atm%7D%20%3D%20%5Cbf%20688%5C%20mL" />
b)<img src="https://tex.z-dn.net/?f=V_2%20%3D%20%5Cfrac%7B650%5C%20torr%5Ccdot%20800%5C%20mL%7D%7B800%5C%20atm%7D%20%3D%20%5Cbf%20650%5C%20mL" />
c)<img src="https://tex.z-dn.net/?f=V_2%20%3D%20%5Cfrac%7B650%5C%20mm%5C%20Hg%5Ccdot%20800%5C%20mL%7D%7B320%5C%20mm%5C%20Hg%7D%20%3D%20%5Cbf%201%5C%20625%5C%20mL" />
d)<img src="https://tex.z-dn.net/?f=V_2%20%3D%20%5Cfrac%7B650%5C%20torr%5Ccdot%20800%5C%20mL%7D%7B100%5C%20torr%7D%20%3D%20%5Cbf%205%5C%20200%5C%20mL" />.