Question
An air bubble of volume 1.0 cm3 rises from the bottom of a lake 40m deep at a temperature of 12°C. To what volume does it grow when it reaches the surface, which is at a temperature of 35° C?
Solution
At the bottom of the lake,
Volume of air bubble, V = 1.0 cm3
Depth of lake = 40 m
Temperature, T = 12o C = 12+273 K = 285 K
At the top of the lake
Volume of air bubble = ?
Changed temperature, T' = 35o C
Pressure at the top of the lake, Pt = 1 atm = 1.01 Pa
Volume at the top, Vt = ?
Now using the gas equation, we have
is the required volume of the air bubble at the surface.