A Cold Trap Is Set Up to Cause Molecules to Linger

A cold trap is set up to cause molecules to linger near the suction in a vacuum system. If the cold trap has an effective volume of 0.200 L and is maintained at 13.0 K, how many molecules are in it at 10.0 Pa of pressure? (Avogadro's number is 6.022 × 10²³ molecules/mol, and the universal gas constant is 8.314 J/mol•K. Assume the behavior of an ideal gas.)

A) 1.11 × 10¹⁹ molecules
B) 1.10 × 10²² molecules
C) 7.71 × 10²⁰ molecules
D) 7.71 × 10²³ molecules