Question on PPI Sample Exam - Help please

[Baconbit]

Okie Dokie - A couple of questions here -

PPI Env Eng Sample Exam #3, solution for question 237 (pg. 105) - I got this one wrong because I doubled the area (since in the problem, it indicates that there are 2 adsorber vessels). Apparently, I'm not supposed to account for the doubled area because the solution doesn't do that? Any advice? It says "2 adsorber vessels...in a lead-follow configuration."

These next 2 questions could just be because it's after midnight and my brain likely isn't working, but here goes - on questions 242 and 243 in that sample sample exam #3, where are they getting the delta G and delta H values for lead, OH and lead hydroxide? I am lost...

Any help is appreciated. Just keep telling myself that it will all be over in 3 days. ;-)

 

[RIP - VTEnviro]

I've got the book at home but am at work right now, so I don't know about the first one.

The delta-G and delta-H values are available in standard tables. I had them from an envl chem class I took in college, but I suspect you can download them. Does the ENVRM have any thermo tables in it? It's been 3 years since I started spamming here took the exam, so I'm not hip to what's in the book right now.

 

[klk]

I am loaning all my review materials to some friends taking the exam this week, so I can't help out specifically with the problems. One thing though I wanted to point out is that I don't remember ever having to look up values of anything (if someone remembers differently, please speak up). Everything (and more) I needed was stated in the problem statement, because they want to eliminate the possibility that someone is using a different constant from a different reference or something.

 

[Dleg]

Once again it's been a while, but I think the reason you only compute the area of the vessel once is because the question is asking for the "adsorption vessel hydraulic loading rate", and the configuration of "lead-follow" would indicate a serial arrangement, so hydraulically, the flow "sees" only one cross sectional area; not two. Simple, right?

I concur with klk that you will very unlikely be required to look up any values of constants, those were pretty much always supplied. My best guess is that NCEES doesn't want to worry about fighting over correct answers that differ due to different values being provided by different references, which does happen (especially with some of the chemical properties)

 

[Stokey]

Hi Baconbit - I did the same thing on # 237 (I had considered the volume of two vessels instead of one). After seeing the solution and reading the question, I came to the conclusion that I had read the question wrong, as Dleg suggested below. I don't remember the other two questions but I will post again if I can answer your other questions. I took the exam last year and also remember that much of the information was provided in the problem statement (along with information you don't need). I think I only had to know water density, molecular weight of CaCO3 and really basic stuff like that (but I had good references with me just in case...!)

 

[RIP - VTEnviro]

Once again it's been a while, but I think the reason you only compute the area of the vessel once is because the question is asking for the "adsorption vessel hydraulic loading rate", and the configuration of "lead-follow" would indicate a serial arrangement, so hydraulically, the flow "sees" only one cross sectional area; not two. Simple, right?

I agree, that makes a lot of sense the way you explained it. The flow is not being split in parallel, in which case each vessel would see half the HLR. Putting it in series is basically breaking up one looooong tank to make it the equipment fit in your treatment room.

I don't remember ever having to look up values of anything (if someone remembers differently, please speak up). Everything (and more) I needed was stated in the problem statement, because they want to eliminate the possibility that someone is using a different constant from a different reference or something.

The only stuff I recall having to look up was established constants: specific gravity of gasoline, viscosity of water, etc. and Federal standards/requirements.

Everything else was given to eliminate ambiguity. I ran into something similar when I was practicing the PPI sample exams.

There was an inflow/infiltration question for a sewer. No I&I rate was given so I used the value in our state standards. Got the problem wrong as they assumed a different value, despite my method being correct.

 

[FLBuff PE]

...There was an inflow/infiltration question for a sewer. No I&I rate was given so I used the value in our state standards. Got the problem wrong as they assumed a different value, despite my method being correct.

I would have given you partial credit...wait, multiple choice. No partial credit available. D'oh!

 

[GTjoy]

I never got that far in the Sample Exams... I didn't have time to take a "real time" practice exam, for that matter, either.

I was only able to review the NCEES sample exam and PPI/Schneiter Sample Exam #2. I'm kind of wishing I had taken the whole week off, I think I could have gone through all the sample exams and reviewed my weak areas too. Oh well, nothing I can do now!!