Multiple Choice
A gas bottle initially contains 0.800 mol of gas at a pressure of 730 mm Hg. If the final pressure is increased to 1.15 atm, how many moles of gas were added to the bottle, assuming constant temperature and volume?
7. Gases
The Ideal Gas Law
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A sample of argon gas has a volume of 735 mL at a pressure of 1.20 atm and a temperature of 112 °C. What is the final volume of the gas, in milliliters, when the pressure is changed to 0.80 atm and the temperature to 25 °C, assuming the amount of gas remains constant?
A
735 mL
B
900 mL
C
500 mL
D
1,200 mL
Verified step by step guidance1
Identify the initial and final conditions of the gas: Initial volume (V1) = 735 mL, initial pressure (P1) = 1.20 atm, initial temperature (T1) = 112 °C, final pressure (P2) = 0.80 atm, and final temperature (T2) = 25 °C.
Convert the temperatures from Celsius to Kelvin by adding 273.15 to each: T1 = 112 + 273.15 K and T2 = 25 + 273.15 K.
Use the combined gas law, which is \( \frac{P_1 \cdot V_1}{T_1} = \frac{P_2 \cdot V_2}{T_2} \), to relate the initial and final states of the gas.
Rearrange the combined gas law to solve for the final volume (V2): \( V_2 = \frac{P_1 \cdot V_1 \cdot T_2}{P_2 \cdot T_1} \).
Substitute the known values into the equation and solve for V2: \( V_2 = \frac{1.20 \text{ atm} \cdot 735 \text{ mL} \cdot (25 + 273.15) \text{ K}}{0.80 \text{ atm} \cdot (112 + 273.15) \text{ K}} \).
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