I need to find the mass of butane gas and I only know the following things (you cannot use the molar mass of butane):
volume = 80 mL
pressure = 98.23 KPa
temp.= 298K
So I found the number of mols and I got 0.003171814 mols. of butane.
But I don't know what to do after this since I can't use molar mass.
Use PV = nRT to get the number of moles, n. You already did that.
You need the molar mass to get the mass of butane. Any ideal gas with that P, V and T will have the same number of moles.
More facts are needed or the question cannot be answered
To find the mass of butane gas without using the molar mass, you can use the ideal gas law equation:
PV = nRT
where:
P is the pressure in Pascals (Pa)
V is the volume in cubic meters (m³)
n is the number of moles of gas
R is the ideal gas constant (8.314 J/(mol·K))
T is the temperature in Kelvin (K)
Since you have the volume, pressure, and temperature, you can rearrange the equation to solve for the number of moles (n):
n = PV / (RT)
Plugging in the given values:
P = 98.23 kPa = 98,230 Pa (convert to Pascal)
V = 80 mL = 0.080 L = 0.080 dm³ = 0.080/1000 m³ (convert to cubic meters)
T = 298 K
n = (98,230 Pa) * (0.080/1000 m³) / ((8.314 J/(mol·K)) * 298K)
Simplifying the equation, you'll get the number of moles of butane.
Once you have the number of moles (0.003171814 mol), you can proceed to find the mass using the following formula:
mass = number of moles * molar mass
However, since you mentioned that you can't use the molar mass of butane, you won't be able to calculate the mass using this method. The molar mass of butane (C₄H₁₀) is 58.12 g/mol.
If you don't have access to the molar mass of butane or any additional information, you won't be able to find the mass of butane gas solely based on the given information.