We are given:_______________________________________________
Volume of Gas (V) = 2.5L
Pressure (P) = 1.2 atm
Temperature (T) = 25°C OR 25+273 = 298 K
Universal Gravitational Constant (R) = 0.0821
Solving for number of moles:___________________________________
From the Ideal Gas Equation,
PV = nRT
(1.2)(2.5) = n(0.0821)(298) [plugging the given values]
n = [(1.2)(2.5)] / [0.0821*298]
n = 300 / [298*8.21]
n = 0.12 moles
Hence, there are 0.12 moles of Oxygen in 2.5L of 1.2 atm gas when the temperature is 25°C