Expert: Henry Boyter - 9/24/2001

Question
Hello.  I'm the dad of a very curious four year old (Alex) who's latched onto the periodic table like a pit bull.  Now he wants to know why we can't take some sodium and some chlorine and mix em together to make salt (I think he learned that salt was sodium chloride on the web site www.brainpop.com.)  I looked on google to see if there were any experiments where people made their own salt crystals.  But I didn't see anything like that.  I saw where you could take salt water and distill the salt from it.  But that's not what he's looking for.  If you have any thoughts on why we could or could not make salt from its constituent parts - I'd look smarter.  :-)  Thanks!  

-Michael

Answer
The activation energy is too high.  That is the enrgy that it takes to get over the hump to where you are going.  Look that up on google.  It can be done in the gas phase (not easy).  In water, both Na and Cl2 (note Cl is not the natural state) would rather react with the water.

You can make salt crystals by dissolving salt in water, then letting the water evaporate.  Hang (from a pencil or stick) a piece of string or dental floss in the middle of the container (not to the bottom) to give it a site to start.  The more salt the better, but it all has to be dissolved to begin with.  Try the string at different depths in different shape and sizes of  jars.  By the way, you distill the water, not the salt.  Salt is a solid up to about 5000 degrees.