Question

Difficulty: MediumGeneral Gas Law, Ideal Gas Equation, and Molar Volume

A fixed mass of an ideal gas occupies a volume of 3.0 dm33.0\text{ dm}^3 at 27C27^\circ\text{C} and a pressure of 1.0 atm1.0\text{ atm}. What is the final volume of the gas in dm3\text{dm}^3 when the temperature is increased to 127C127^\circ\text{C} while maintaining constant pressure?

Answer: 4.0 / 4 / 4.0 dm3 / 4 dm3 / 4.0 dm³ / 4 dm³

Answer

The final volume of the gas is 4.0 dm34.0\text{ dm}^3.
First convert temperatures to Kelvin: T1=27+273=300 KT_1 = 27 + 273 = 300\text{ K} and T2=127+273=400 KT_2 = 127 + 273 = 400\text{ K}. At constant pressure, V1T1=V2T2\frac{V_1}{T_1} = \frac{V_2}{T_2}. Rearranging to solve for V2V_2 gives V2=3.0×400300=4.0 dm3V_2 = \frac{3.0 \times 400}{300} = 4.0\text{ dm}^3.

Step-by-Step Solution

1
Convert both temperatures from degrees Celsius to Kelvin
T1=27+273=300 KT_1 = 27 + 273 = 300\text{ K} and T2=127+273=400 KT_2 = 127 + 273 = 400\text{ K}
Gas law calculations strictly require absolute temperature measured in Kelvin.
2
Apply Charles's Law derived from the ideal gas equation (PV=nRTPV = nRT) at constant pressure
V1T1=V2T2\frac{V_1}{T_1} = \frac{V_2}{T_2}
Volume is directly proportional to absolute temperature when pressure and amount of gas are constant.
3
Substitute the values into the formula and solve for V2V_2
V_2 = \frac{V_1 \times T_2}{T_1} = \frac{3.0 \times 400}{300} = 4.0\text{ dm}^3
Calculates the new gas volume.

Key Concept

General Gas Law and Absolute Temperature Conversion
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