Jump to content


Photo

Decahydrate to monohydrated conversion // processing

D19 raw chemical processing

  • Please log in to reply
2 replies to this topic

#1 JayneAmaraRoss

JayneAmaraRoss
  • Basic Members
  • PipPip
  • 27 posts
  • Director
  • Paris, France

Posted 11 June 2013 - 12:35 PM

Dear all,

I am mixing up a batch of my usual kodak D19 developer (for Tri-X super8) with a new stock of raw chemicals.

The sodium carbonate that I have just bought is decahydrate and my formula calls for monohydrated.

Does anyone know how to convert the monohydrated weight to decahydrate?

The D19 needs 52.5g monohydrated.

All suggestion are welcome

Jayne


  • 0

#2 Brian Pritchard

Brian Pritchard
  • Basic Members
  • PipPipPipPip
  • 328 posts
  • Other
  • Stoke-on-Trent, UK

Posted 12 June 2013 - 05:41 AM

The calculation is based on the molecular weight of the chemical:  Sodium carbonate is Na2Co3  which has a molecular weight of (2 X 23) + 12 + (3 x 16) = 106  Water is H2O which has a molecular weight of (2 X 1) +16 = 18.  So decahydrate has a molecular weight of 106 + (10 X 18) = 286. The molecular weight of monohydrate is 106 + 18 = 124.  The equivalent weight of decahydrate to monohydrate is 286/124 so you would need 52.5 x 286/124 gms of decahydrate = 121 gms.  

 

I have a formula that uses anhydrous Sodium Carbonate the amount is 45 gms.  So using the above calculation monohydrate would need 45 X 124/106 = 52.6 gms which is what you have quoted.

 

I hope this is clear.

Brian


  • 0

#3 JayneAmaraRoss

JayneAmaraRoss
  • Basic Members
  • PipPip
  • 27 posts
  • Director
  • Paris, France

Posted 18 June 2013 - 11:06 AM

Hi Brian,

Sorry for the late reply. 

Thank you very much for your help, it really saved my darkroom session!

All the best,

Jayne


  • 0


rebotnix Technologies

Willys Widgets

FJS International, LLC

Metropolis Post

Broadcast Solutions Inc

Glidecam

Rig Wheels Passport

CineTape

Wooden Camera

Visual Products

Aerial Filmworks

Gamma Ray Digital Inc

Ritter Battery

CineLab

The Slider

Media Blackout - Custom Cables and AKS

Tai Audio

Technodolly

Paralinx LLC

Opal

Abel Cine

Tai Audio

The Slider

Metropolis Post

Technodolly

CineLab

FJS International, LLC

CineTape

Rig Wheels Passport

Broadcast Solutions Inc

Visual Products

Ritter Battery

Opal

Paralinx LLC

Abel Cine

Gamma Ray Digital Inc

Willys Widgets

Media Blackout - Custom Cables and AKS

rebotnix Technologies

Glidecam

Aerial Filmworks

Wooden Camera