A teacher has found two wh te powders on a desk in the chemistry laboratory. She wants to test to see if they are pure substances, so she
measures the melting points. Substarce X meits at 1225C and substance Y
meits between 87 and 93°C. Explain which one is the pure substance.

Ifound this on google “laws of chemical combination. it states that matter can neither be created nor destroyed. it stated that a given compound always contains exactly the same proportion of elements by weight.” i hope this you for what your looking for.

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na