Given:
Standard Temperature and Pressure (STP) is defined as a temperature of 0°C (273.15 K) and a pressure of 1 atm.
Step 1: Understand the molar volume at STP
At STP, the molar volume of any ideal gas is \( 22.4 \, \text{L/mol} \). This means that one mole of an ideal gas occupies 22.4 L at STP.
Answer: The correct answer is option (1): 22.4 L/mol.