Multiple choice

At the top of a mountain, a thermometer reads 7oC and barometer reads 70 cm of Hg. At the bottom of the mountain, they read 27oC and 76 cm of Hg. Compare the air at the top with that at the bottom.

  1. 0.9868

  2. 3.55

  3. 1.01

  4. 0.28

  5. 0.072
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 According to gas equation, PV =  µRT PV = (M/Mw)RT      [as µ = M/Mw] Or P/ρT = R/Mw    [as M/V = ρ] Now as M and R are same for top and bottom (P/ρT)T = (P/ρT)B  i.e., ρT /ρB  = (PT/PB) x (TB/TT) So, ρT/ρB = (70/76) x (300/280)                 = 75/76                =  0.9868  

Keep practicing — related questions