Perry's Table Typo? 2

[Canoman]

I'm looking at Perry's 7th Ed., Table 2-5, Vapor Pressure of Liquid Water from 0 to 100°C. Is this a typo?

33.2°C, Pvap = 38.155 mmHg
33.3°C, Pvap = 38.369 mmHg
33.4°C, Pvap = [highlight]33[/highlight].584 mmHg (Should this be 38.584??)
33.5°C, Pvap = 38.801 mmHg
33.6°C, Pvap = 39.018 mmHg
33.7°C, Pvap = 39.237 mmHg
33.8°C, Pvap = 39.457 mmHg

 

[Montemayor]

Canoman:

I’m using the NIST database and I get:

Temp. oC V.P. mmHg
33.200 38.19475
33.300 38.40926
33.400 38.62528
33.500 38.84205
33.600 39.05957
33.700 39.27859
33.800 39.49836

So I don’t even get your data. However, it seems like Perry made another typo boo-boo. That’s one reason why I don’t use Perry’s for data like this.

Besides being FREE, complete, authoritative, and downloadable, the NIST datatables available on the Web are the way to go for water thermo data - as well as for the refrigerants.

 

[Canoman]

Thanks Montemayor... Didn't even think of checking NIST for this.

 

[EGT01]

In case you're interested, I checked my copy of Perry's 6th, and the same table is presented in it but the width is reduced so it takes up only half of the page. That's Table 3-5 in the 6th edition.

At first glance, it looks like the data in the 6th edition shows the same as the 7th but my eyes ain't what they used to be. Using my trusty magnifying glass, it looks like the type on the "8" is broken so it just looks like a "3".

 

[StoneCold]

Canoman
I have the seventh edition and it shows 33 as well. Obviously a typo.
While the nist data is different you have to ask your self is it really going to make any difference that you will see in the field?

My opinion only

StoneCold

 

[quark]

I extensively refer steamtab for steam and water properties as this is one good offline reference. I checked the values with that of Mr Montemayor's and they are exact to 3 decimal places.

http://www.chemicalogic.com/steamtab/companion/default.htm

However, I agree with StoneCold in my world of calculations but, I don't know, Chemical Engineers may need a better precision.

Regards,

 

[katmar]

This error has been around for a while, but has got worse with time! The oldest Perry I have with me at the moment is a 4th Ed. (1963). In this version the pressure at 33.4°C is gives as "3 .584 mmHg", i.e. there is a blank space between the 3 and the decimal point. But looking at the columns on either side of this entry make it obvious that it should be 38.584.

Somebody must have tried to fix it at some stage, and made it worse by entering wrong data. At least in the 4th Ed it was obvious that there was a problem.

This type of printing mistake, while not common, is also seen in other references as well. Years ago, before we had the internet and easy access to data like NIST, I developed my own correlations for steam tables. When testing them against Perry and other sources I found a few typos. Most were insignificant, but it showed me the advantage of using a correlating formula rather than a look-up table because errors like this are eliminated.

Katmar

 

[Canoman]

I actually started with looking up the data from "Elementary Principles of Chemical Processes" 2nd. Ed. by Felder & Rousseau, but it had more errors than Perry's.