Question 19
Gas LawsAs a result of air at the top of a barometer, the height of the mercury column is 73.5 cm when it should be 75.0 cm; the volume of the space above the mercury is 8.0 cm3. Calculate the correct barometric height when the barometer reads 74.0 cm and the volume of the space above the mercury is 6.0 cm3.
- A.72.0 cm
- B.74.5 cm
- C.75.1 cm
- D.76.0 cm.
Show the answer and explanation
Answer: D (76.0 cm.)
Explanation
The trapped air's pressure is first 75.0 − 73.5 = 1.5 cmHg. Boyle's law: 1.5 × 8 = p × 6, so p = 2 cmHg. True height = 74.0 + 2 = 76.0 cm.