Answer:
The molar mass of the gas is 140.86 g/mol
Step-by-step explanation:
Step 1: Data given
Mass of the gas = 0.555 grams
Volume of the gas = 117 mL = 0.117 L
Temperature = 85 °C
Pressure = 0.99 atm
Step 2: Calculate the number of moles
p*V = n*R*T
⇒ with p = the pressure of the gas = 0.99 atm
⇒ with V = the volume = 0.117 L
⇒ with n = the number of moles
⇒ with R = the gas constant = 0.08206 L*atm/K*mol
⇒ with T = the temperature of the gas = 85 °C = 358.15 Kelvin
n = (p*V)/(R*T)
n = (0.99 * 0.117)/(0.08206 * 358.15)
n = 0.00394 moles
Step 3: Calculate molar mass of the gas
Molar mass = mass / moles
Molar mass = 0.555 grams / 0.00394 moles
Molar mass = 140.86 g/mol
The molar mass of the gas is 140.86 g/mol