Final answer:
By calculating the molar mass of the gas (32 g/mol) using its given mass and volume at STP, we identified that the gas is oxygen (O₂), as it matches the known molar mass of oxygen.
Step-by-step explanation:
To find out the identity of the gas with a mass of 0.96 grams occupying a volume of 0.672 L at STP (standard temperature and pressure), we first need to calculate its molar mass. At STP, one mole of any ideal gas occupies 22.4 L. The molar mass (MM) of a substance is calculated by dividing the mass of the gas by the mols of the gas. Using the volume of the gas and its relationship to molar volume, the number of moles can be found.
First, calculate the number of moles (n) of the gas using the molar volume at STP:
n = volume of gas / molar volume at STP = 0.672 L / 22.4 L/mol = 0.03 mol
Next, calculate the molar mass:
MM = mass of gas / n = 0.96 g / 0.03 mol = 32 g/mol
Now, compare this calculated molar mass to the molar masses of the options provided:
- O₂: 32 g/mol
- N₂: 28.0 g/mol
- CO₂: 44.0 g/mol
- CH₄: 16.0 g/mol
The calculated molar mass matches the molar mass of O₂ (oxygen) which is 32 g/mol. Therefore, we can conclude that the identity of the gas is oxygen, O₂.