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 $1.0 \times 10 ^ { - 7 } \mathrm {~Pa}$ If the volume of the chamber is $0.500 m ^ { 3 }$ and the temperature is $27 ^ { \circ } \mathrm { C }$ how many molecules are left inside chamber? $\left( N _ { \mathrm { A } } = 6.022 \times 10 ^ { 23 } \mathrm { molecules } / \mathrm { mol } , R = 8.31 \mathrm {~J} / \mathrm { mol } \cdot \mathrm { K } \right)$

A) $2.4 \times 10 ^ { 13 }$
B) $1.2 \times 10 ^ { 14 }$
C) $1.2 \times 10^{13}$
D) $1.2 \times 10^{12}$
E) $2.4 \times 10 ^ { 12 }$