All Problems

Equation of the gas state processes

Problem 2.10

A smooth vertical tube having two different sections is open from both ends and equipped with two pistons of different areas (Fig. 2.1). Each piston slides within a respective tube section. One mole of ideal gas is enclosed between the pistons tied with a non-stretchable thread. The crosssectional area of the upper piston is ΔS=10 cm2\Delta S=10 \mathrm{~cm}^{2} greater than that of the lower one. The combined mass of the two pistons is equal to m=5.0 kgm=5.0 \mathrm{~kg}. The outside air pressure is p0=1.0p_{0}=1.0 atm. By how many kelvins must the gas between the pistons be heated to shift the pistons through l=5.0 cm?l=5.0 \mathrm{~cm} ?

Reveal Answer
ΔT=(mg+p0ΔS)l/R=0.9 K\Delta T=\left(m g+p_{0} \Delta S\right) l / R=0.9 \mathrm{~K}