Insoluble ionic compounds and insoluble metallic compounds could both have high melting points, insolubility, and no conductivity in water. Is there a way to distinguish between the two in a laboratory setting?

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    $\begingroup$ How well does solid salt conduct electricity? Now how about solid copper? $\endgroup$ – Oscar Lanzi Nov 16 '18 at 0:54
  • $\begingroup$ Welcome to Stack Exchange! Could you edit your question? It doesn't make sense right now: "Insoluble ionic compounds and insoluble ionic compounds..." I'd edit, but I'm not sure if you mean insoluble/soluble ionic compounds, or insoluble ionic compounds and metallic compounds. $\endgroup$ – miltonaut Nov 16 '18 at 1:02
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    $\begingroup$ @miltonaut Ok, thank you! I just edited the question. $\endgroup$ – mokim Nov 16 '18 at 1:17
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    $\begingroup$ Whack it with a hammer. Metals are malleable and ionic salts are not. $\endgroup$ – MaxW Nov 16 '18 at 1:46
  • $\begingroup$ @MaxW The compound we used were in tiny pieces. Is there another method I could have used? $\endgroup$ – mokim Nov 16 '18 at 2:05

As solids, metals...

  1. conduct heat and electricity well (ionic solids do not)
  2. are malleable and ductile (ionic solids are not)
  3. have lower melting points and boiling points than ionic solids

Test these properties by...

  1. applying heat and a thermometer; using a conductivity apparatus (larger/chunk samples)
  2. hit the sample with a hammer as MaxW suggested (larger/chunk samples)
  3. test for relative melting/boiling points by applying equal amounts of heat (granular samples)
  • $\begingroup$ What if the unknown substance was in little pieces (like iron filings) and there were only conductivity testers that worked on solutions? I'm just curious if there is another method. $\endgroup$ – mokim Nov 16 '18 at 3:45
  • $\begingroup$ Test #3 - relative melting points. The "points" of a substance are intensive properties. As long as you have similar amounts, and equipment to carry out the tests, it should work. $\endgroup$ – miltonaut Nov 16 '18 at 6:40

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