How many atoms of argon occupy 20.00 mL if the temperature is 200°C and the pressure is 2.00 × 10-3 Torr?
A) 2.01 * 10 17
B) 6.02 * 10 -17
C) 3.10 * 10 17
D) 2.44 * 10 19
E) 2.80 * 10 -11

Question

How many atoms of argon occupy 20.00 mL if the temperature is 200°C and the pressure is 2.00 × 10-3 Torr?
A) 2.01 * 10 17 
B) 6.02 * 10 -17 
C) 3.10 * 10 17 
D) 2.44 * 10 19 
E) 2.80 * 10 -11

Quizplus · Accepted Answer

To solve this, we use the ideal gas law equation PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature in Kelvin. First, convert everything to the correct units: 200°C = 473.15 K, 20.00 mL = 0.02000 L, and 2.00 × 10^-3 Torr = 2.67 × 10^-6 atm (using 1 atm = 760 Torr). Then, solve for n (moles of argon) and convert moles to atoms using Avogadro's number (6.022 × 10^23 atoms/mol). The calculation leads to an answer in the order of 10^19 atoms, which matches option D.

How Many Atoms of Argon Occupy 20