Question 5
Gas Laws30cm3 of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C.
- A.40.0 cm3
- B.35.7 cm3
- C.28.4 cm3
- D.25.2 cm3
Show the answer and explanation
Answer: C (28.4 cm3)
Explanation
Pressure of dry hydrogen = 780 − 10 = 770 mmHg at 300 K. V2 = 770 × 30 × 280/(300 × 760) ≈ 28.4 cm3.