Which of the following is true regarding gases at STP? Molar volume can be used at any temperature. The mol or volume of a gas can only be found using PV = nRT. 22.4 mol of gas occupies 1 L . 1 mol of gas occupies 22.4 L .

Let's evaluate each statement regarding gases at **Standard Temperature and Pressure (STP)**, where STP is typically defined as **0°C (273.15 K)** and **1 atmosphere (atm)** pressure. 1. **Molar volume can be used at any temperature.** - **False.** Molar volume is specific to the conditions of temperature and pressure. At STP, the molar volume of an ideal gas is **22.4 liters per mole (L/mol)**. If the temperature changes, the volume occupied by a mole of gas will also change according to the ideal gas law. 2. **The mol or volume of a gas can only be found using PV = nRT.** - **False.** While the **Ideal Gas Law (PV = nRT)** is a fundamental equation for calculating the number of moles (n) or the volume (V) of a gas, it's not the only method. Other gas laws, such as **Boyle’s Law**, **Charles’s Law**, and **Avogadro’s Law**, can also be used depending on the specific conditions and known variables. 3. **22.4 mol of gas occupies 1 L.** - **False.** At STP, **1 mole** of an ideal gas occupies **22.4 liters**. Therefore, **22.4 moles** would occupy **22.4 × 22.4 = 501.76 liters**. 4. **1 mol of gas occupies 22.4 L.** - **True.** This is a standard definition at STP for an ideal gas. **1 mole** of an ideal gas indeed occupies **22.4 liters** under these conditions. **Conclusion:** Only the **fourth statement** is true regarding gases at STP. **Answer:** Only the fourth statement is correct. At STP, one mole of gas occupies 22.4 liters.