Gas Law Chemistry

Question

At STP, 7.0 grams of CO gas will occupy a volume of 4.07 L at 718 mm Hg, what is the temperature?

Answer 1

At STP, 1 mole of any ideal gas will occupy 22.4 liters. So, at STP, 7.0 grams of CO will not occupy 4.07 L and the pressure will not be 718 mm Hg. These are NOT conditions of STP (standard temperature and pressure). So, let's assume that the question does NOT say at STP, but rather reads,...

7.0 g of CO gas will occupy a volume of 4.07 L at 718 mm Hg and what is the temperature?

PV = nRT

T = PV/nR

T = temperature in Kelvin = ?

P = pressure = 718 mm Hg x 1 atm/760 mm Hg = 0.945 atm

V = volume in liters = 4.07 L

n = moles = 7.0 g CO x 1 mol CO/28 g = 0.25 moles

R = gas constant = 0.0821 Latm/Kmol

T = (0.945 atm)(4.07 L) / (0.25 mol)(0.0821 Latm/Kmol)

T = 187K