Question

Boron trifluoride gas is collected at in an evacuated flask with a measured volume of . When all the gas has been collected, the pressure in the flask is measured to be . Calculate the mass and number of moles of boron trifluoride gas that were collected. Round your answer to significant digits.

Answer 1

Answer:

0.683 mol

46.3 g

Explanation:

There is some info missing. I think this is the original question.

Boron trifluoride gas is collected at 21.0 °C in an evacuated flask with a measured volume of 50.0 L. When all the gas has been collected, the pressure in the flask is measured to be 0.330 atm. Calculate the mass and number of moles of boron trifluoride gas that were collected. Round your answer to 3 significant digits.

Step 1: Convert the temperature to the Kelvin scale

We will use the following expression.

K = °C + 273.15

K = 21.0°C + 273.15

K = 294.2 K

Step 2: Calculate the moles of boron trifluoride gas

We will use the ideal gas equation.

$P \times V = n \times R \times T\\n = \frac{P \times V}{R \times T} = \frac{0.330atm \times 50.0L}{\frac{0.0821atm.L}{mol.K} \times 294.2K} = 0.683 mol$

Step 3: Calculate the mass of boron trifluoride gas

The molar mass of BF₃ is 67.81 g/mol.

$0.683 mol \times \frac{67.81g}{mol} = 46.3 g$