Which of the following gas samples has the same volume as 16.0 g of oxygen? (All volumes are measured at the same temperature and pressure) A - Scottish Highers Chemistry - Question 23 - 2023

At standard temperature and pressure (STP), one mole of an ideal gas occupies 22.4 L. Therefore, the volume of 0.500 mol of oxygen is:

$V = n \times 22.4 \ L/mol = 0.500 \ mol \times 22.4 \ L/mol = 11.2 \ L$

Now, we will calculate the moles for each gas sample to find which has the same volume of 11.2 L:

• Carbon monoxide (CO): Molar mass = 28.0 g/mol $n = \frac{21.0 \ g}{28.0 \ g/mol} = 0.750 \ mol$ $V = 0.750 \ mol \times 22.4 \ L/mol = 16.8 \ L$

• Carbon dioxide (CO₂): Molar mass = 44.0 g/mol $n = \frac{44.0 \ g}{44.0 \ g/mol} = 1.0 \ mol$ $V = 1.0 \ mol \times 22.4 \ L/mol = 22.4 \ L$

• Nitrogen dioxide (NO₂): Molar mass = 46.0 g/mol $n = \frac{46.0 \ g}{46.0 \ g/mol} = 1.0 \ mol$ $V = 1.0 \ mol \times 22.4 \ L/mol = 22.4 \ L$

• Dinitrogen tetroxide (N₂O₄): Molar mass = 92.0 g/mol $n = \frac{46.0 \ g}{92.0 \ g/mol} = 0.500 \ mol$ $V = 0.500 \ mol \times 22.4 \ L/mol = 11.2 \ L$

Based on the calculations, the gas sample that has the same volume as 16.0 g of oxygen is:

D. 46.0 g of dinitrogen tetroxide