4-56E Determine the enthalpy change A h of oxygen, in Btu/lbm, as it is heated from 800 to 1500 R, using (a) the Page 199 empirical specific heat equation as a function of temperature (Table A–2Ec @), (b) the cp value at the average temperature (Table A–2Eb O ), and (c) the cp value at room temperature (Table A-2Ea ). Answers: (a) 170 Btu/lbm,(b) 169 Btu/lbm, (c) 153 Btu/lbm

Fig: 1