A Laboratory Vacuum Pump Can Reduce the Pressure in a Chamber

Multiple Choice

A laboratory vacuum pump can reduce the pressure in a chamber to 1.0 × 10^-7 Pa.If the volume of the chamber is 0.500 m³ and the temperature is 27°C,how many molecules are left inside the chamber? (N_A = 6.022 × 10²³ molecules/mol,R = 8.31 J/mol ∙ K)

A) 1.2 × 10¹³
B) 2.4 × 10¹³
C) 1.2 × 10¹²
D) 2.4 × 10¹²
E) 1.2 × 10¹⁴