Recent content by Dong Aleta

Actually, it's a precipitate after mixing solutions of K2HPO4 and CaCl2, after filtration and drying.

I apologize for not specifying. I want to precipitate hydroxyapatite (HAP) by mixing two solutions of K2HPO4 and CaCl2 at initial pH 9~9.5. I did some literature review and found out that apparently, we know of other calcium phosphate crystals can precipitate other than HAP. But I want to be...

I want to know of any standard method for identifying (and possibly quantifying) the species contained in a solid mixture sample. Thanks in advance!

Hey, thanks for the response! Yeah, I'm familiar with nomographs. I just can't determine what the variables in the graph represent. But thanks a lot for this information! I really appreciate it!

Hi, I was asked by my senior to find out what this graph is and how to use it. No details were given as to where they found it. I know already that this is used to compare CSTRs and PFRs performance for first order reactions, but I can't deduce what the expressions Dd/(vxL) and kL/vx are for...

I see. That's really confusing. Anyway, thank you!

Hi! I read from Perry Green's ChE Handbook that the friction factor for Re ≤ 2,100 can be approximated by ƒ = 16/Re. But there was this question that I encountered (though I don't know the source) and according to it, ƒ = 64/Re for laminar flow. Can someone clarify which is which? Thank you!

I thought so too, but I had to check. I imagined there to be a differential form of this. But anyway, thanks for the response!

In the energy balance of a system where a small object at T1 enclosed in a body at T2 given by the Stefan-Boltzmann equation q = A1ε1σT14 - A1α12σT24 shouldn't it be a differential equation since the small body could be absorbing/releasing sufficient net energy from the enclosing body that...

Hi! I encountered this problem that asked for the friction factor of a very dilute SO2-air gas mixture in a wetted wall column. All the necessary information were given to compute for the Reynold's number. What I want to know is does having a wetted wall make it a different case (ergo use...

I see. Thanks a lot for the input! I really appreciate it. :)

What I meant by "compounds" are those non-monoatomic ones. Like, CaO(s) + H2O(l) -> Ca(OH)2, where calcium retains its +2 oxidation state, hydrogen its +1, and oxygen its -2. Or CaO(s) + CO2(g) -> CaCO3 where calcium still retains +2, carbon +4, and oxygen -2.

Hi! I was looking at some problems in Geankoplis' book on Transport Processes and Unit Ops and I came across this problem involving water at 85°C, atmospheric pressure. The problem required the enthalpy of the water and so the book used the enthalpy of saturated water at 85°C from a steam...

I see! Thank you again for the response! Much appreciated!

Sorry, I'd like to add a follow-up question. I just came across this web page that said "Not all hydroxides are strong bases since not all hydroxides are highly soluble" suggesting that solubility has something to do with the basicity of the substance. Is the web page incorrect with its...