How many molecules of an ideal gas occupy 1.00 mL at 300 C and 10 -3 torr?

To find the number of molecules of an ideal gas occupying 1.00 mL at 300°C (573 K) and 10⁻³ torr, we can use the Ideal Gas Law (PV = nRT). First, convert the pressure from torr to atm (10⁻³ torr = 1.32 x 10⁻⁵ atm) and the volume from mL to L (1.00 mL = 0.001 L). Using R = 0.0821 L·atm/(K·mol), we calculate n (the number of moles) and then convert moles to molecules using Avogadro's number (6.022 x 10²³ molecules/mol). The result is approximately 2.65 x 10² molecules.