Re cooking washing powder than has clumped

[Bobby]

 Kephra,
  Just a quick ? will the grams per 100 ml of dist water for 1 mol remain the same as pre cooked washing powder? thanks, Bobby

[kephra]

Arm and Hammer Super Washing Soda from the grocery store is sodium carbonate monohydrate, meaning that each molecule has 1 water molecule attached. 
Making washing soda from baking soda has no water attached, (anhydrous) so it is lighter, and you need less by weight.

Use 12.4 grams for A&H washing soda vs 10.6 grams of converted baking soda.

If you bake your washing soda, then its 10.6 grams.

[RickinWI]

 I think that to make it exactly 1 Molar you are supposed to use 10.6 gm (for Anhydrous) and combine it with enough DW "to make up" 100 ml of solution. Not sure but I would think that the 10.6 gm of Sodium Carbonate would take up some space so my question is if we put 10.6 gm into 100 ml (100 gm) of water then would our solution be slightly less than 1 M?  If so then is there a way to figure the exact amount of DW to add to the 10.6 gm to make it exactly 1M?

I think in a lab they do this by adding the powder & then filling a very accurate graduated cylinder to the exact amount.

[Bobby]

   Kephra & RickinWI,
     Thank you very much. It's finally as I thought it should be. I figured it would be lighter and it was. And I did make the first batch of 1 Molar starting with 100 ml of DW. Now I will mix &  then bring it up to the100 ml level with DW. I really want to get the little things right while the roll of cash for the Elite grows. Kephra, you ever  thought of putting all the valuable info from this forum to sell on CD or downloads to the members to cover cost of operations & not lose all this knowledge? There are people out there that are very very afraid of what is being done her. This website helps me get through the day. Bobby

[kephra]

Not sure but I would think that the 10.6 gm of Sodium Carbonate would take up some space so my question is if we put 10.6 gm into 100 ml (100 gm) of water then would our solution be slightly less than 1 M?

RickinWI:  Yes, adding the washing soda to 100ml would make it more than 100ml.

Chemistry lesson for today
Interestingly, there are some substances that when added together take up less space.  IE: 50 ml of pure alcohol + 50 ml of water makes less than 100ml of solution. 
See https://www.quora.com/Thermodynamics/Why-does-the-H2O-Ethanol-solution-have-less-volume-than-the-pure-components for an explanation.

[RickinWI]

Pretty amazing how that example has less volume than the 2 liquid components.

So I know the answer will be less than 100 gm of DW and more than 89.4 gm of water to get to exactly 1M Na2CO3.

Since I don't have an accurate graduated cylinder I think I will take a wild guess & go with 97 gm of water. I'm thinking that would be very close to 1 M with the 10.6 gm of Anhydrous Sodium Carbonate. Guess it's just splitting hairs.

[kephra]

Well you don't really have to know,  just put 10.6 grams into a container marked at 100ml and add water to the mark.  Most common measuring cups have metric markings on them, or put 3 ounces plus 2 teaspoons of water in a glass and mark the glass at the top of the water.  Thats close enough for horseshoes and hand grenades.