A sample of gas has a mass of 0.555g. volume is 117 mL at a temperature of 85 degrees Celsius and a pressure of 0.99 atm. What is the molar mass of the gas?

The molar mass of the gas is 140.86 g/mol

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

Answer: 0.04 moles

Explanation:

pV = nRT

p=pressure = 0.99atm

v = volume = 117ml = 0.117L

n = number of moles = n

T = temperature = 85 + 273 = 358k

R = rate constant = 0.082 L. atm/kmol

n = pV/RT = 0.99 X 0.117 / (0.082 X 358)

= 0.004 moles