Chapter 6, Problem 6.7CU

answer 96,97,98

1. thermodynamics

answer 99 and 100

2. An ideal gas undergoes a process from state 1 ( T1= 300 K, P1= 100 kPa) to state 2 ( T2= 600 K, P2 500 kPa). The specific heats of the ideal gas are : c, = 1 kJ/kg-K and c, = 0.7 kJ/kg-K. The change in specific entropy of the ideal gas from state 1 to state 2 (in kJ/kg-K) is (correct to two decimal places).

The entropy of an ideal gas depends on both T and P. The function s° represents only the temperature-dependent part of entropy.

Answer 94 and 95

Argon gas flows through a well-insulated nozzle at steady state. The temperature and velocity at the inlet are 550°R and 150 ft/s, respectively. At the exit, the temperature is 480°R and the pressure is 40 lb/in?. The area of the exit is 0.0085 ft². Use the ideal gas model with k-1.67, and neglect potential energy effects. Determine the velocity at the exit, in ft/s, and the mass flow rate, in lb/s. Step 1 Your answer is correct Determine the velocity at the exit, in ft/s. V₂- 677.088 Hint Step 2 ft/s Determine the mass flow rate, in lb/s, through the nozzle. m = i lb/s Attempts: 2 of 4 used

for steam, the specific ideal gas constant = 461.5 J/kg K A closed system is comprised of pure water substance initially at a temperature of 500 oC and a pressure of 20 MPa (state 1). The system undergoes an isochoric process whereby its pressure drops to 0.1 Mpa (state 2). Sketch the process on a Temperature-specific entropy plot, showing the lines of constant pressure which pass through steps 1 and 2.

ANS COMPLETELY AND SURE