Final answer:
The gases will not remain separate and are likely to mix when the flask valve is opened. The gas will rush out, and at 0°C and 1 atm of pressure, 3 grams of a gas with a molar mass of 20 g/mol would occupy approximately 3.36 L, not the full 10 L of the flask.
Step-by-step explanation:
Let's examine the scenarios presented for the behavior of 3 grams of a gas with a molar mass of 20 g/mol when the valve to a sealed 10-L flask is opened:
- The gas and air will remain separate and will not mix. False. Gases tend to diffuse and mix due to the random motion of molecules, regardless of the initial separation between the gas in the flask and the air outside.
- The gas and air will mix and the gas will react with oxygen in the air. This statement could be true or false, depending on the chemical properties of the gas in question. Without specific information on the reactivity of the gas, a definitive answer cannot be provided.
- The gas will rush out of the bottle. True. When the valve is opened, the gas will move from the region of higher pressure inside the flask to the lower pressure outside, causing it to rush out.
- At 0°C, the three grams of gas will still occupy 10 L. To determine if this is true or false, we should use the ideal gas law. Given the molar mass (20 g/mol), we have 0.15 mol of gas. At 0°C (273 K) and 1 atm, one mole of an ideal gas occupies 22.4 L. Hence, our 0.15 mol would occupy about 3.36 L (0.15 mole × 22.4 L/mol), suggesting this statement is false; the gas at 0°C and 1 atm would not occupy the full 10 L of the flask.