What volume is occupied by 1.00 kg of helium at 5.00◦C at a pressure of 735 Torr?

1. 1.06 × 102 L

2. 5.90 × 103 L

3. 5.60 × 103 L

4. 5.97 × 105 L

5. 2.95 × 103 L

1 Answer

  • The key to solve such kind of problems is to first be familiar with the given. Then we choose which formula will be suitable to solve this problem. Here, we’re given the pressure, temperature, the mass of the gas, and we indeed know the atomic weight of He, which is 4 g/mol, and we’re looking for the volume.

    Hence. we use the ideal gas law. I’ll use the gass constant R as 0.0821 Latm/molK.

    Solution:

    PV = nRT

    (735/760 atm)V = (1000 g / 4 g/mol)(0.0821)(278 K)

    0.967105263V = (250 mol)(0.0821)(278 K)

    0.967105263V = 5705.95 (Divide both sides by 0.967105263)

    V = 5900.029933 or 5.9 x 10^3 L (Answer)

    Choose number 2.

    Hope this helps!

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