Calculate the amount (in moles) of Ar in the gas sample.

Question

A sample of Ar gas has a volume of 475 mL, has a pressure of 976 mm Hg, and is at a temperature of 23.5 °C. Calculate the amount (in moles) of Ar in the gas sample.

__mol

Answer 1

Use the ideal gas law - PV = nRT where P is pressure in atm, V is volume in liters, n is moles, R is the gas constant (0.08206 liter-atmosphere/mole Kelvin), and T is in K

976mmHg/760 = 1.28 atm

475 mL = 0.475 L

23.5 C = 296.7 K

n = PV/RT

n = 1.28 x 0.475/0.08206 x 296.7

n = 0.025 moles