Finding the internal energy using a steam table

[smoothie king]

Homework Statement

What is entropy of water at 5 Bar and an internal energy of 2724 kJkg-1?

The Attempt at a Solution

I have looked at the steam tables, i found where the pressure is 500kpa, then i do not know where to go from there.

Thank You

 

[phinds]

So you will be supplied with tables that no one has told you how to use? Really?

 

[smoothie king]

So you will be supplied with tables that no one has told you how to use? Really?

i have changed the question around

 

[smoothie king]

i have changed the question around

sorry for double post, i pressed something wrong by accident.

 

[Chestermiller]

Let me understand correctly. You have steam tables, and you know that you have water at 5 bars with an internal energy of 2724 kJ/kg, and you are asked to determine its entropy. Is that right?

Chet

 

[smoothie king]

Let me understand correctly. You have steam tables, and you know that you have water at 5 bars with an internal energy of 2724 kJ/kg, and you are asked to determine its entropy. Is that right?

Chet

Yes, that's exactly what I'm trying to do, i didnt know how to change the title and i didnt want to start a new thread.

 

[Chestermiller]

You found a place in the tables where the pressure is 500 kPa. What is the heading on the top of the page (e.g., saturated steam or superheated steam)?

Chet

 

[smoothie king]

You found a place in the tables where the pressure is 500 kPa. What is the heading on the top of the page (e.g., saturated steam or superheated steam)?

Chet

Superheated Steam

 

[Chestermiller]

Superheated Steam

OK. Now there are columns of numbers on the page. What are the headings on the columns of numbers?

Chet

 

[smoothie king]

OK. Now there are columns of numbers on the page. What are the headings on the columns of numbers?

Chet

They are all temperatures from 100°c to 700°c

 

[Chestermiller]

They are all temperatures from 100°c to 700°c

What are the headings on the other columns (or rows?)?

Chet

 

[smoothie king]

What are the headings on the other columns (or rows?)?

Chet

there is t(sat), then h and s for all the temperatures above. also hg and sg for saturation

 

[Chestermiller]

there is t(sat), then h and s for all the temperatures above. also hg and sg for saturation

I thought you said that the part of the table you were open to was for superheated steam. This table is for saturated steam. What gives?

Chet

 

[smoothie king]

I thought you said that the part of the table you were open to was for superheated steam. This table is for saturated steam. What gives?

Chet

i have two tables and i didn't notice, i have one with h and s, another with u and v, i just realized that i have to find the value for temperature in the u and v table using internal energy, then use that temperature to find the value of entropy in the h and s table. I got the value of entropy to be 7.272.

Thank you very much!

 

[Chestermiller]

i have two tables and i didn't notice, i have one with h and s, another with u and v, i just realized that i have to find the value for temperature in the u and v table using internal energy, then use that temperature to find the value of entropy in the h and s table. I got the value of entropy to be 7.272.

Thank you very much!

Sounds about right.

Chet