# Chemical Forums

• February 21, 2019, 03:29:29 AM
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 1   on: Today at 01:09:27 AM Started by kdbmvp - Last post by kdbmvp Total pressure was probably the wrong word. It just says: how much N2 can be solved in 1L of water at 20 celsius and 1 atm pressure. Not sure if I entirely understood your answer?

 2   on: Today at 12:10:37 AM Started by kdbmvp - Last post by Enthalpy What does this "total pressure" mean? If it's 1atm of air, then 0.78atm of N2 is reasonable. If it's 1atm of N2, you need to scale down to 0.78atm.

 3   on: Yesterday at 11:25:48 PM Started by kdbmvp - Last post by kdbmvp Hello,How much N2 can be solved in 1L of water at 20 celsius, 1 atm total pressure, if the partial pressure of the N2 gas is 0.78atm? From a table I found that the solubility of N2 in water at 20 celsius is 0.0190 g/L, at a total pressure of 1 atm. The solution manual calculates it this way:0.78atm*0.0190 g/L = 0.01482 g/L. But is this correct? From how I understand the task the answer should just be 0.0190 g/L

 4   on: Yesterday at 09:32:53 PM Started by throwaway57 - Last post by Borek You are right - reaction as written is not balanced.

 5   on: Yesterday at 02:11:42 PM Started by Biostartup - Last post by wildfyr Sodium azide isn't very sensitive, but say, chromium or iron azide is. You can create those on the surface of a stainless steel spatula by ion exchange.

 6   on: Yesterday at 01:58:26 PM Started by throwaway57 - Last post by throwaway57 I’m very confused by the problem in a packet my teacher gave me, which states Al(s) + N2(g)  2ALN(s)I reviewed this question with my teacher and he said it was correct, however wouldn’t that make the equation imbalanced, since there isn’t 2 Aluminum atoms on the left side of the equation?

 7   on: Yesterday at 01:50:12 PM Started by Wanderer0 - Last post by Wanderer0 I'm currently reproducing an experiment for a case study, and it concerns a topical application of horseradish ﻿peroxidase (lyophilised, 200IU/mg, dissolved in water, activated by H2O2 15%, in a 15% H2SO4 buffer).H2O2 was stored at 4°C, diluted with H2O stored at room temperature, the buffer was also at room temperature, and the process was conducted at 20°C.Working with peroxidase for ﻿the first time, I'm having doubts regarding application and handling. I've diluted the HRP with water 1 ml/mg, activated and added the buffer in a ceramic dish, and applied the mixture at room temperature using a PVC syringe, and covered over the area with a cellulose gause ﻿to ensure that the surface would remain soaked for 30 minutes). Total fluid volume was 50 cubic centimetres.﻿I have had no surface effect, possibly due to storing HRP at 4°C for 10 weeks?﻿Also, could the transfer in a pvc syringe affect﻿ ﻿the HRP activity, or could the covering of the surface with﻿﻿ gauze draw HRP activity from the surface.Is there a more preferred way of applying the﻿ composition on the surface (mixing the diluted HRP, activator and buffer on the surface itself than leaving them on for 30 minutes? Or preparing them beforehand in a pvc spray bottle and applying them for 30 minutes without gauze cover? Or using glassware, avoiding﻿ PVC (which makes the application a bit trickier).Thank you in advance for your replies.

 8   on: Yesterday at 10:33:17 AM Started by Jason Schmit - Last post by Corribus At chemical forums we do not provide advice about how to make medications, drugs, cosmetics or edible products. Therefore this response is addressing the digestibility aspect of the question, not the edibility aspect of it.Although hair is basically protein, the keratin component of hair is tough and resists digestion even in harsh conditions because of the numerous dissulfide bonds that hold peptide strands together. The best way to digest hair is to first use a process that can hydrolyze these bonds, rendering the proteins easily digested by normal peptide digestion methods. You can buy keratinase at many chemical manufactures that should be able to do this under reasonably mild conditions - although these can be expensive depending on how much hair you are trying to digest.https://www.sigmaaldrich.com/catalog/product/sigma/k4519?lang=en®ion=USTreatment with reductants like beta mercaptoethanol (or TCEP) may provide an alternative chemical means of loosening the dissulfide structure, rendering hair digestible.If all else fails, high temperature acid or alkaline digestion will also probably work, but a properly equipped chemistry lab and technical knowledge will be required to do this safely and effectively.To restate: just because a protein is rendered digestible does not mean it's edible. Any chemical treatment can introduce unsafe chemical residues that would need to be effectively removed before you could actually ingest anything you make or transform in the lab. This process would probability be more difficult than the problem of making keratin able to be digested in the first place.

 9   on: Yesterday at 10:30:15 AM Started by Legolasas5 - Last post by Legolasas5 Hello there,I am trying to optimise HPLC method and I have a problem with 2 peaks that change their selectivity depending on elution conditions. Is it appropriate to have a negative resolution as a response in the DoE table if these peaks switch.Thank you for your answers.

 10   on: Yesterday at 09:34:29 AM Started by Didi2604 - Last post by Borek I believe (can be wrong though) Pharmacopoeia can be a good starting point.

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