Answer: .819 Moles of Air
Explanation: To solve this problem, we will use the Ideal Gas Law which states that PV=nRT. P represents pressure or internal pressure, V is volume, T is temperature, n is moles of a gas, and R is the Universal Gas Constant. For the ideal gas law, R is .08206. R is 8.314 for any other calculation. We are solving for the moles of gas. The gas in this case is air which is a mixture of gases but that isn't important.
Our givens are P = 7.3 atm, V = 2.67 L and T = 17.0°C. We convert T to Kelvin because the Ideal Gas Law requires that. We simply add 273 to the value in Celcius to convert it to Kelvin. Our T is now 290 K. We also know R is our Universal Gas Constant. We can now plug into the law.
(7.3 atm)(2.67 L) = n(.08206)(290 K)
n = ((7.3 atm)(2.67 L))/(.08206)(290 K)
n = .819 moles of air
Hope this helps!