Sarah and maria mixed some iron filings with yellow sulfur powder. both iron and sulfur are elements in the periodic table. the girls used a magnet to separate the iron filings from the sulphur. next, the girls poured the two elements in a test tube and heated the mixture in a flame. the two elements melted and black smoke came out of the test tube. the two liquids seemed to combine. when the girls stopped heating the test tube, there was a shiny black solid inside. the took a magnet and held it up to the new substance but nothing happened. why?