Paul Sutton


Solute calculator

There is website tool for calculating the amount of solute needed for a given volume and concentration. This can be found here

I just put this together in python3


#Chemical solute calculator
print("Chemical solute calculator")
print(" ")
print("This program will ask you for some basic data and will then calculate how much solute is needed for a given volume and concentration")
print(" ")
print("1 mol solution is formula weight in 1 liter of water")
print(" ")
print("Mass is the molecular mass of the chemical solution you're making e.,g Copper Sulfate is 249g")
print(" ")
print("Volume the total solution volume in litres,  100ml is written as 0.100")
print(" ")
print("Concentration required in Mols")
print(" ")
mass = input ("Mass in g: ") 
#print("Solute requred")
volume = input("Volume in l: ")
print((volume) + " l")
conc = input ("Required Concentration in M: ") 

solute = float(mass) * float(volume) * float(conc)
print("Solute required: ")
print(str(solute) + " g")
print(" ")
print("Note:  This program is a guide, and you should double check calculations")
#Chemical solute calculator
print("Chemical solute calculator")
print(" ")
print("This program will ask you for some basic data and then calculate how much solute is needed for a given volume and concentration")
print(" ")
mass = input ("Mass in g: ") 
print("Solute requred")
volume = input("Volume in l: ")
print((volume) + " l")
conc = input ("Required Concentration in M: ") 

solute = float(mass) * float(volume) * float(conc)

Note: This is just meant to work and perform a single function. I have not added error checking, so values are numerical.



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Every Author as First Author

This looks like a great idea

    We propose a new standard for writing author names on papers and in bibliographies, which places every author as a first author -- superimposed. This approach enables authors to write papers as true equals, without any advantage given to whoever's name happens to come first alphabetically (for example). We develop the technology for implementing this standard in LaTeX, BibTeX, and HTML; show several examples; and discuss further advantages. 



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Home Chemistry 11 – Making a Citric Acid solution

Further to the previous post on making molar solutions I am going to make up a 250ml solution of Citric acid.

So based on my previous calculations

1 Molar solution is formula weight in 1 litre of Water

Molar Weight of Citric acid 192.19 Amount of Water = 250ml (0.250 l)


192.19 / 4 = 48.03g

I can weigh this out easy enough now that I have got some small scales (which are actually used for weighing jewellery) but are really good as they measure to 2 decimal places. Granted max is about 200g, but for what I am doing in chemistry this doesn't matter too much.

make citric acid 1

The first task is to weigh out the required amount of Powder.

make citric acid 2

Given I wanted 48.03g, I think for the purpose of home chemistry this is fine.

make citric acid 3

For the next step I mixed the powder with about 200ml water, stirred well then poured (via funnel) in to a conical flask and topped up to about 250ml (note the flask is approximate.) I may be just over. in a proper laboratory, I would have access to a volumetric flask, which is more accurate. I am making do with what I have.

I would probably have access to some help with this too.

make citric acid 4

Finally, the solution is poured (via funnel) in to a suitable bottle, that I have already put a label etc on.

This is now stored safely before being taken down to the Library.

We can then use this for various experiments such as adding to alkalis, using indicator (paper or liquid) or whatever else we decide to do).

There is a really nice calculation tool which you can use to help or at least double check calculations.


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Home Chemistry 3 – Molar Solutions

Last year, I had a go at preparing a known concentration 1M of Sodium Chloride (Salt). Using the instructions at Quora.

In order to some chemicals for future use. I will use the same instructions to create a known concentration of Citric Acid, given I want to test the reactivity between this and various metals, in a similar way to my previous experiment in Home Chemistry 1


  1. Decide how much solution is needed – 250ml
  2. Determine Molar mass of Citric Acid
    • According to PubChem this is 192.12g
  3. Work out how much solid powder is needed
    • Given 1 Mol is the molecular weight in 1 litire of water
  4. We are producing 250ml – so need to weigh out ¼ of the molar mass
    • 192.12 / 4 = 48.03g
  5. So based on the instructions I found for NaCl
  6. We need to dissolve 48.03g in 250ml of Water to produce 250ml 1 molar concentration of Citric Acid


  1. Refer to data sheet – We know that Citric Acid is a Irritant, therefore it would be prudent to stick the CORRECT label on the bottle storing the solution.
  2. Correctly label the bottle
  3. Wear goggles when preparing the solution
  4. Wear gloves and Lab Coat
  5. Clean Surfaces
  6. Wash hands when finished


  • Scales or Balance
  • Volumetric Flask *1
  • Stirrer
  • Spatula
  • Paper to write notes
  • Paper to put on scales for powder
  • Funnel
  • Label saying 250ml 1 mol Citric Acid
  • Label giving formula and Molar weight
  • Irritant label

Equipment Replacement

*1 As I don't have a volumetric Flask, I can use a 250 or 500ml Conical Flask


My weighing scales are only basic and do not measure to 2 decimal places, there for we can weigh out 48g. As this is for home chemistry, while accuracy is important, we can probably make minor compromises.


  • Water
  • Citric Acid Powder


Read fully first

  1. Prepare equipment
  2. Measure out 250ml Water
  3. Fold paper in ½
  4. Unfold paper
  5. Put paper on scales
  6. Ensure Scales are ZERO
  7. Weigh out required amount of Citric Acid Powder
  8. Pour powder in to flask and stir or move flask around in a circular motion*
  9. Pour solution in to suitable container
  10. Stick on labels
  11. Wash up and dry equipment
  12. Wipe down surfaces etc
  13. Wash hands
  14. Store solution safely

Note the fold in the paper,just makes this easier.

  • You may need to pour small amounts in to the flash, and dissolve before adding more

Further reading and advice

There will be a related thread on Science Forums for this, as I want to double check everything is correct.



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Making chemical solutions

An important part of Chemistry is the ability to make up solutions of a known concentration. This can sound quite complex, however it doesn't need to be.

The following is some simple instructions that will produce 250m of 1molar concentration of Sodium Chloride

I have made this solution up using pure Sodium Chloride, from a chemical supplier [1], rather than table salt which contains Sodium Ferrocyanide. If you need extra help with this try asking on Science forums [2] as there is a section on there for home chemistry.

I am also on the IRCNow network, where we are starting up a channel to discuss amateur / home science.


1 Better Equipped 2 Science Forums 3 Amateur Science



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Youtube-dl out of date

The youtube-dl tool on Debian 10 is out of date, it seems even the sid version is behind, by a good few months.

After some searching I have found a way to fix this.

Please note you need to do you OWN RESEARCH in to fixing this. I am not responsible for loss or problems caused by following what I have put here.

Firstly I was getting the following error

youtube-dl [youtube] 0JSHubLg7NE: Downloading webpage [youtube] 0JSHubLg7NE: Downloading video info webpage ERROR: 0JSHubLg7NE: YouTube said: This video is unavailable.

The webpage here was a little helpful


In providing an explanation and some fixes.

Firstly on Debian the internal update option is disabled so

youtube-dl -U

Won't work, reading further this seems to download the latest version

While the above instructions worked for me, The old version was still installed, this needs to be removed so doing this before hand may help.

However if you want to check the current version before removing you can use:

youtube-dl —version

Then remove with:

apt remove youtube-dl -

The instructions

wget -O /usr/local/bin/youtube-dl

You will still need to change the permissions as per above website. I am not repeating them here, you need to read up.

However – Debian appears to expect youtube-dl to be in /usr/bin.

The above solution downloads to /usr/local/bin/youtube-dl, you can either put in the path manually when running as in:


Which gets rather tedious to keep doing that.

In order to get round this, I have copied the binary to where Debian wants it

cp /usr/local/bin/youtube-dl /usr/bin/youtube-dl

Which seems to work for me, but is probably the wrong way to go about doing this.

You can now find the version that is now installed by using

youtube-dl —version


Hopefully this is useful. You need to do your own research but the problem is fixable.

Once you have upgraded you can download youtube videos in the normal way with youtube-dl.

#debian, #youtube-dl, #error, #fix, #solution, #gnu, #linux

You can find me on Friendica at

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Licenced under Attribution 4.0 International (CC BY 4.0)

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