Final answer:
To identify the unknown gas given its weight compared to oxygen gas under the same conditions, we calculate its molar mass, which is found to be 76.00 g/mol. The unknown gas with a molar mass closest to this value is carbon disulfide (CS₂). So the correct answer is option C.
Step-by-step explanation:
To determine which unknown gas is given in the question, we will use the ideal gas law and stoichiometry concepts. We know that equal volumes of gases under the same conditions of temperature and pressure contain the same number of moles. Since the volume is the same for both oxygen gas and the unknown gas, we can establish a relationship between their moles based on their respective molecular weights.
One mole of oxygen gas (O₂) weighs 32.00 grams. If 1.00 gram of O₂ is given, this corresponds to ⅘32 moles. On the other hand, if 2.375 grams of the unknown gas is given, this will correspond to an equal number of moles as that of the oxygen since the volumes are equal under the same conditions.
Thus, the molar mass (molecular weight) of the unknown gas can be calculated as follows:
The molar mass of unknown gas = ⅘ g / (⅘32 moles) = 76.00 g/mol.
Examining the choices, the molar mass of NO (A) is 30.01 g/mol, SO₂ (B) is 64.07 g/mol, CS₂ (C) is 76.14 g/mol, and CO (D) is 28.01 g/mol. The closest molar mass to our calculated value is that of carbon disulfide, CS₂.