Question

A 1.39-g sample of an unknown gas has a volume of 989 mL and a pressure of 463 mm Hg at 59.8 °C. Calculate the molar mass of this compound.

Answer 1

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Answer 2

To calculate the molar mass of the unknown gas, we can use the ideal gas law equation: PV = nRT. By plugging in the given values and solving for the number of moles, we can then calculate the molar mass by dividing the mass of the sample by the number of moles. The approximate molar mass of the unknown gas is 61.5 g/mol.

Step-by-step explanation:

To calculate the molar mass of the unknown gas, we can use the ideal gas law equation:

PV = nRT

Where:

• P is the pressure (in atm)
• V is the volume (in L)
• n is the number of moles
• R is the gas constant (0.0821 L·atm/(mol·K))
• T is the temperature (in Kelvin)

First, let's convert the given pressure from mm Hg to atm:

463 mm Hg * (1 atm / 760 mm Hg) = 0.6097 atm

Next, let's convert the given volume from mL to L:

989 mL * (1 L / 1000 mL) = 0.989 L

Now we can plug in the values into the ideal gas law equation:

(0.6097 atm) * (0.989 L) = n * (0.0821 L·atm/(mol·K)) * (59.8 °C + 273.15)

Solving for n:

n = (0.6097 atm * 0.989 L) / (0.0821 L·atm/(mol·K) * 333.95 K) = 0.0226 mol

Finally, we can calculate the molar mass by dividing the mass of the sample by the number of moles:

Molar mass = 1.39 g / 0.0226 mol = 61.5 g/mol

Therefore, the approximate molar mass of the unknown gas is 61.5 g/mol.