<p>I recently did a lab involving finding the empirical formula of a hydrated salt. We burned the salt until all the water evaporate and we were only left with salt. I found that my compound was about 30% salt and the accepted value was 51 % thus giving me a ngative percent error. What are 3 sources of error in this situation? Any help would be greatly appreciated. Thanks.</p>
<p>salt leaving with the water vapor, measuring errors, and burnt salt? I don’t know</p>
<p>Maybe it reabsorbed moisture from the air</p>
<p>1) The salt reacted with some gases in the air, leaving a slightly lighter compound. This would happen if you burned it too much.</p>
<p>2) You accidentally filtered out too much salt at some point earlier in the experiment, leaving you with too little at the final step.</p>
<p>3) Presence of impurities in the mixture; your mixture contained some solid other than the salt whose mass you wanted to find.</p>
<p>If you described the experimental procedure it would be easier to find out where things may have gone wrong.</p>