2300_hw_4_sol

# 2300_hw_4_sol - data Assumptions The process is...

This preview shows page 1. Sign up to view the full content.

Solutions for 4 4-15 Air in a cylinder is compressed at constant temperature until its pressure rises to a specified value. The boundary work done during this process is to be determined. Assumptions 1 The process is quasi-equilibrium. 2 Air is an ideal gas. Properties The gas constant of air is R = 0.287 kJ/kg.K (Table A-1). Analysis The boundary work is determined from its definition to be kJ 272 - = = = = = kPa 600 kPa 150 ln K) K)(285 kJ/kg kg)(0.287 (2.4 ln ln 2 1 2 1 1 2 1 1 ou , P P mRT P d P W t b V Discussion The negative sign indicates that work is done on the system (work input). 4-23 Several sets of pressure and volume data are taken as a gas expands. The boundary work done during this process is to be determined using the experimental
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: data. Assumptions The process is quasi-equilibrium. Analysis Plotting the given data on a P-diagram on a graph paper and evaluating the area under the process curve, the work done is determined to be 0.25 kJ . 3-2C A liquid that is about to vaporize is saturated liquid; otherwise it is compressed liquid. 3-10C At supercritical pressures, there is no distinct phase change process. The liquid uniformly and gradually expands into a vapor. At subcritical pressures, there is always a distinct surface between the phases. 3-14C Yes. Otherwise we can create energy by alternately vaporizing and condensing a substance. P 1 2 T =...
View Full Document

## This note was uploaded on 09/04/2009 for the course CHEM 2300 taught by Professor Thermo during the Summer '08 term at Utah.

Ask a homework question - tutors are online