what volume in mL will 320 grams of oxygen gas occupy at 25 degree celsius and 79 kPa and a 7 atm of pressure, if it occupies 0.4 liters at STP

Answer 1

There are two questions being asked here, I believe.

What is the volume of O2 gas at 79 kPa pressure, and what is the volume O2 gas at 7 atm pressure.

First, find the volume O2 gas at STP, where 1 mole of gas = 22.4 liters

moles of O2 = 320 g x 1 mole/32 g = 10 moles of gas

10 moles x 22.4 liters/mole = 224 liters of gas at STP (273K, 1 atm)

Using the combined gas law of P₁V₁/T₁ = P₂V₂/T₂

When temperature (T2) is 25 = 295K and P2 is 7 atm...

V2 = (1 atm)(224 L)(298K)/(273K)(7 atm) = 3.43 liters

When temperature (T2) is 25 = 298K and P2 is 79 kPa (79 kPa x 1 atm/103 kPa = 0.767 atm)

V2 = (1 atm)(224 L)(298)/(273)(0.767 atm) = 319 liters