At 25oC temperature and 730 mm pressure, 380 mL of dry oxygen was collected. If the temperature is h — States of Matter and Gaseous State Chemistry Question
Question
At 25oC temperature and 730 mm pressure, 380 mL of dry oxygen was collected. If the temperature is held constant, what volume will be oxygen occupy at 760 mm pressure?
💡 Solution & Explanation
# Solution: Gas Volume Change with Pressure Since temperature is constant, we apply **Boyle's Law**: $P_1V_1 = P_2V_2$ **Given:** - Initial pressure: $P_1 = 730$ mm Hg - Initial volume: $V_1 = 380$ mL - Final pressure: $P_2 = 760$ mm Hg - Final volume: $V_2 = ?$ - Temperature: constant at 25°C **Calculation:** $$P_1V_1 = P_2V_2$$ $$730 \times 380 = 760 \times V_2$$ $$V_2 = \frac{730 \times 380}{760}$$ $$V_2 = \frac{277,400}{760} = 365 \text{ mL}$$ **Why this is correct:** When external pressure increases (730 → 760 mm Hg), the gas volume decreases inversely at constant temperature. The final volume (365 mL) is smaller than the initial volume (380 mL), which is physically reasonable—increased pressure compresses the gas.