A lightbulb filled with argon gas has a volume of 75 mL at STP. How many moles of argon gas does the lightbulb contain?

0.00335 moles

Explanation:

From the question, Using

PV = nRT ... Equation 1

Where P = pressure, V = Volume, n = number of moles of argon gas, R = Molar gas constant, T = Temperature.

make n the subject of the equation

n = PV/RT ... Equation 2

Given: P = 1 atm (standard pressure), T = 273 K (standard temperature), V = 75 mL = 0.075 dm³

Constant: R = 0.082 atm·dm³/K·mol

Substitute into equation 2

n = (1*0.075) / (273*0.082)

n = 0.075/22.386

n = 0.00335 moles