If a sample container of CO2 (g), occupies a volume of 435 mL at a pressure of 0.987 atm and a temperature of 25 C. What is the volume of gas at STP?

The volume is 0,393 Liters (393 ml)

Explanation:

We use the formula PV=nRT. We clear n (number of moles). STP conditions are 1 atm pressure and 273 K temperature. The temperature in Kelvin = 25+273=298K. The volume in L: 435/1000 = 0,435 L.

PV=nRT n=PV/RT n = (0,987 atmx0, 435 l) / (0,082 l atm/K mol x298K)

n=0,0176 mol

In conditions STP:

PV = nRT V = (nRT) / P

V = 0,0176 mol x 0,082 l atm / K mol / 1 atm = 0,393 L