how many moles are there in 40 litres of co2 and STP
Answers
Answer:
AT STP, 40 L CO2 will contain about 2 moles CO2.
Explanation:
Molar Volume
In 1982, the IUPAC, the International Union of Pure and Applied Chemistry, recommended changing standard pressure to exactly 1 x 10^5 Pascals (Pa), which is exactly 100 kPa and 1 bar. Using this standard, the molar volume of a gas is 22.711 L/mol. Using 1 atm for standard pressure, the molar volume of a gas is 22.414 L/mol.
The previous answer gave moles of 40 L of CO2 using 1 atm and 22.4 L/mol, which is still widely used. However, using the 1982 standard, we can calculate moles using the same formula, but using an updated molar volume.
n=V/Vm, where: n=moles=?, V=volume=40 L, Vm=molar volume=22.711 L/mol
Since Vm is a fraction, we can divide by multiplying by its reciprocal, 1 mol/ 22.711 L. This will cancel volume and leave moles.
n=40 L CO2 x (1 mol/22.711 L) = 1.761 mol CO2 = 2 mol CO2 rounded to two significant figures
Ideal Gas Law
We can also solve this using the equation for the ideal gas law, the general gas equation:
PV=nRT, where:
P=pressure=1 x 10^5 Pa = 1 bar
V=volume=40 L
n=moles=?
R=gas constant=(0.08314 L*bar)/(K*mol)
T=temperature=273.15 K
You can rearrange the general gas equation to isolate n.
n=PV/RT
Substitute the known values into the equation and solve. Instead of dividing by the gas constant, I am multiplying by its reciprocal (K*mol)/(0.08314L*1bar). This will cancel liters, bars, and Kelvins, leaving moles.
n=(1bar*40L)*((K*mol)/(0.08314L*1bar)*(273.15 K))=1.761=2 mol CO2 to one significant figure
AT STP, 40 L CO2 will contain about 2 moles CO2.