Physic Labs

Problem 2

One mole of monatomic ideal gas initially at absolute temperature TiT_i and pressure pp is heated slowly at constant pressure to Tf>TiT_f>T_i. It obeys pV=RgTpV=R_gT, where RgR_g is the gas constant; neglect macroscopic kinetic and potential energy changes. Take work done by the gas and heat entering it as positive. (a) Find the volume change and work done by the gas. (b) Find the change in internal energy. (c) Find the heat added and the ratio of heat to work.
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Q=ΔU+W=52RgΔTQ=\Delta U+W=\frac52R_g\Delta T
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With work by the gas positive, the first law is Q=ΔU+WQ=\Delta U+W. Both terms are positive during this isobaric heating.