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Please help me. We just did an experiment wherein we used Fe, Al, Zn, Sn, Cu and HCl to see their reaction (e.g. Fe + HCl, Al + HCl...). The result of the experiment:

1.) $\ce{Fe + HCl}$ = formed bubbles (56 min)

2.) $\ce{Al + HCl}$ = formed bubbles (more than 1 hour)

3.) $\ce{Zn + HCl}$ = formed bubbles (42 min)

4.) $\ce{Sn + HCl}$ = No reaction

5.) $\ce{Cu + HCl}$ = No reaction

Now with the result, how can I distinguish metals from non-metals?

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    $\begingroup$ Fe, Al, Zn, Sn and Cu are all metals $\endgroup$ – user15489 Sep 12 '15 at 1:49
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Well as santiago has pointed out, they are all in fact metals.

The way you can determine if it is a metal or not is that when any metal reacts with acid, hydrogen gas is released. This is shown in this general equation (it is not balanced): $$\ce{M^{m+} + HCl -> MCl + H2}$$

Meanwhile, generally non-metals don't react with acid. This because when a substance reacts with acid, it electrons to the H+ ions created by the acid. Non-metals are generally electron-accepters, rather than electron donors so there is no way for them to donate electrons to the hydrogen ions in the acid.

In your experiment, the bubbles that formed when reacted are indication that hydrogen gas is being formed, therefore the substance is a metal. Therefore, you should be able to tell that Fe, Al and Zn are metals.

Therefore, you might assume that Sn and Cu have to be non-metals. However they are actually metals. The reason why no bubbling is observed is because these metals are unreactive and don't get oxidised by the acid.

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    $\begingroup$ Well, $\ce{Sn}$ does, only very slowly. $\endgroup$ – Ivan Neretin Sep 12 '15 at 8:10
  • $\begingroup$ True, but I don't think you will be able to see it react given the time restrictions in a school experiment. $\endgroup$ – Nanoputian Sep 12 '15 at 8:22
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    $\begingroup$ Yes, that's right. Could leave it overnight, though. $\endgroup$ – Ivan Neretin Sep 12 '15 at 8:25
  • $\begingroup$ Does that mean that an acid with sufficiently low pH will react to release hydrogen with all metals? Or are there truly "unreactive" metals? $\endgroup$ – feetwet Sep 12 '15 at 13:31

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