Message:

<p>[QUOTE=&quot;-jeffB, post: 2873024, member: 27832&quot;]Others have posted about whether sodium carbonate is <i>hydrated</i>. It looks like there are four stable forms of the stuff:</p><p><br /></p><p>anhydrous -- just sodium carbonate</p><p>monohydrate -- one molecule of water for each molecule of carbonate</p><p>heptahydrate -- seven molecules of water for each molecule of carbonate</p><p>decahydrate -- ten molecules of water for each molecule of carbonate</p><p><br /></p><p>It also looks like the decahydrate tends to lose water easily if it&#039;s left open, and the anhydrous form tends to absorb water easily. But if you&#039;re starting with the decahydrate, you need to use almost three times as much!</p><p><br /></p><p>The box I&#039;ve got is Arm and Hammer brand. Here&#039;s a thread where someone actually tried to test its water content:</p><p><br /></p><p><a href="https://www.flickr.com/groups/53495661@N00/discuss/72157623545233076/" target="_blank" class="externalLink ProxyLink" data-proxy-href="https://www.flickr.com/groups/53495661@N00/discuss/72157623545233076/" rel="nofollow">https://www.flickr.com/groups/53495661@N00/discuss/72157623545233076/</a></p><p><br /></p><p>It looks to me like it ships as the anhydrous form, but tends to absorb some water over time. If you&#039;re being meticulous, you&#039;d want to bake it for an hour or so to drive off any extra water.</p><p><br /></p><p>But how critical <i>is</i> the composition, really, for this application?[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in