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I have been asked for a solution of 4% (w/v) cobalt (II) solution and cannot find anything on the internet or chemtalk about how to make this up from the powder. Can anyone assist me please? Maths wasn't my best subject.

mazcheck wrote: ↑28 Jul 2021, 09:56 I have been asked for a solution of 4% (w/v) cobalt (II) solution and cannot find anything on the internet or chemtalk about how to make this up from the powder. Can anyone assist me please? Maths wasn't my best subject.

Hello,

If you can find the version you require from Chem Supply - we can always source it for you!

4 gms in100 ml of water will do it. 4% cobalt (ll) Chloride is now 11-12 years. hope that helps

Thank you so much Macca.

4g in 96mL water would be more precise. I use a balance - weigh out 4g chemical then add 96g water.

We don't use Cobalt (in any form) at all anymore, I've removed it all due to it's environmental and health affects. Asked people to find alternatives and surprisingly when you ask them to find a less nasty chemical they always do. Just have to push them out of their old ways. I

https://assist.asta.edu.au/sites/assist ... utions.pdf

Hi,
This is one of the resources available to check when making solutions, CSIS is another one, Working in Science, etc, there is always the internet.

Percentage is "x" amount up to 100ml. I am partial to Cobalt Chloride but use all the required PPE, very nice in crystal gardens.

Anna Z wrote: ↑31 Jul 2021, 10:50 We don't use Cobalt (in any form) at all anymore, I've removed it all due to it's environmental and health affects. Asked people to find alternatives and surprisingly when you ask them to find a less nasty chemical they always do. Just have to push them out of their old ways. I

Hi Anna

What do you teachers use in place of Cobalt Chloride?

Catie wrote: ↑17 Aug 2021, 09:10

Anna Z wrote: ↑31 Jul 2021, 10:50 We don't use Cobalt (in any form) at all anymore, I've removed it all due to it's environmental and health affects. Asked people to find alternatives and surprisingly when you ask them to find a less nasty chemical they always do. Just have to push them out of their old ways. I

Hi Anna

What do you teachers use in place of Cobalt Chloride?

Hi Catie, the only prac we do with Cobalt is Le Châtalier's Principle - Equilibrium involving Cobalt (II) ions, we have since filmed that so it is shown as a vid and the teachers now do a version with Copper using HCl and Ethanol. Not as pretty but we just don't have cobalt products onsite anymore.