Multiple choice

A gas mixture contains 4 $gms$ of hydrogen and 42 $gms$ of nitrogen. The fraction of the total pressure exerted by nitrogen is:

  1. $\frac{1}{2}$
  2. $\frac{3}{2}$
  3. $\frac{3}{7}$
  4. $\frac{4}{7}$
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C Correct answer
Explanation

Moles of H2 = 4/2 = 2. Moles of N2 = 42/28 = 1.5. Total moles = 3.5. Mole fraction of N2 = 1.5 / 3.5 = 15/35 = 3/7. The pressure fraction equals the mole fraction.

AI explanation

Using Dalton's law of partial pressures, the fraction of total pressure exerted by a gas equals its mole fraction. The number of moles of nitrogen is 42 divided by 28, which equals 1.5, and the number of moles of hydrogen is 4 divided by 2, which equals 2, making the total moles 3.5. The mole fraction of nitrogen is 1.5 divided by 3.5, which results in 3/7.

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